JCMT/SOFIA Joint Virtual Workshop: Magnetic Fields Spill Secrets Of Star Formation

“Magnetic Fields and the Structure of the Filamentary Interstellar Medium”, a JCMT and SOFIA Joint Virtual Scientific Workshop

 

During the period of 22nd – 25th of June, 2021, a virtual workshop on “Magnetic Fields and the Structure of the Filamentary Interstellar Medium” was held online. This workshop brought together more than 150 staff and user community members of the ground-based James Clerk Maxwell Telescope (JCMT) and the aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) for a range of exciting scientific presentations, papers and discussions.

Much of the meeting discourse focused on the presence of interstellar magnetic fields at a range of size scales, and their impact on the lifecycle of Infrared Dark Clouds (IRDCs). IRDCs are the coldest, densest regions interstellar of Giant Molecular Clouds. Sub-millimeter and infrared observations of these IRDCs are particularly important to astronomers because they play a central role in the formation of stars. As a part of this process, the complex interplay of magnetic fields, gravity, chemistry, pressure and density within these regions gives rise to complex clumpy and filamentary structures, which in turn provide hints about their origins.

Since magnetic fields are invisible, astronomers must use indirect methods to trace them. This is made possible because a large number of  tiny interstellar dust grains in these cold, dense regions tend to become aligned by the local magnetic fields. These large collections of aligned dust grains then polarize the infrared and sub-mm light passing between them, in a manner akin to that of polarized sunglasses lenses. These astronomical polarization effects, the details of which were also discussed extensively during this meeting, can therefore be mapped with instruments such as JCMT’s SCUBA-2/POL-2 and SOFIA’s HAWC+, and have already provided a detailed picture of the competing physical influences within the clouds, and hence their effects on the formation of stars.

For further information, please visit the main workshop page here:

https://sofia-science-series.constantcontactsites.com

Videos of the invited talks are available here:

https://sofia-science-series.constantcontactsites.com/w2-abstracts

Videos of the pre-recorded contributed talks are available here:

https://sofia-science-series.constantcontactsites.com/w2-pre-recorded-talks

 

Formation of the Hub–Filament System G33.92+0.11: Local Interplay between Gravity, Velocity, and Magnetic Field

Figure 1. B-field orientations (segments) sampled on a 12” grid overlaid on 850 μm dust continuum (color and contours), sampled on a 4” grid, of the G33.92+0.11 region. The segments are rotated by 90° to represent magnetic field orientations. The yellow and white segments display the larger than 3 and 2–3 polarization detections. The green contours show the total intensity at 20, 50, 200, 300, 500, 1000, and 
 2000 mJy beam-1.

Interstellar filaments are ubiquitous in molecular clouds, and they are a key intermediate stage toward the formation of stars. Previous observations found that many stars commonly form within clustered environments associated with hub–filament systems (HFSs), where they are formed in a dense hub with numerous radial filaments extending from the central hub (Myers 2009, ApJ, 700:1609). Understanding how HFSs form is a topic of considerable interest since HFSs are the possible transition stage connecting the evolution of filamentary clouds and the formation of protoclusters.

G33.92+0.11 is such an HFS, where two massive protoclusters have been discovered by ALMA within the central 0.6 pc area of a dense hub associated with several few pc- length converging filaments (Liu et al. 2019, ApJ, 871:185). Since the size of the entire HFS is well beyond the maximum recoverable scale of interferometers, JCMT observations are essential to investigate the large-scale environments where the massive HFS could form.

We performed polarization observations using JCMT POL-2 to probe the magnetic field morphology in this 5-pc HFS. It is widely known that this polarized continuum emission originates from the dichoric alignment of interstellar dust grains along magnetic field lines in the interstellar medium through the Radiative Alignment Torques (RATs), and so the observed polarization orientation traces the plane-of-sky magnetic field morphology (Andersson et al. 2015 ARA&A, 53:501).

The magnetic field structure inferred from our POL-2 observations reveals a converging pattern pointing toward the hub center (Figure 1), apparently similar to the converging filamentary structures identified from the dust continuum map shown in the top panel of Figure 2, implying that the evolution of the converging filaments is coupled with magnetic fields.

Figure 2: Differential orientation maps for filament vs. magnetic field, local gravity, and local velocity gradient (from top to bottom), overlaid on the 850 μm intensity. The cyan lines are the identified filaments. The yellow and white segments represent the magnetic field orientations, the red arrows are the projected local gravity, and the magenta arrows show the local velocity gradients. Filled color- coded circles (color wedge) are the pairwise differential orientations.

In order to evaluate the relative importance among gravity, turbulence, and magnetic fields, we used the modified Davis-Chandrasekhar-Fermi technique to estimate the energy scale of these physical parameters (Houde et al. 2009, ApJ, 706:1504). By combining our POL-2 polarization data and the velocity information extracted from the IRAM 30-m C18O (2-1) data, the obtained ratio of kinematic to gravitational energy is 0.10–0.20, and the ratio of magnetic to gravitational energy is 0.05–0.10. Hence, the global gravitational energy dominates the kinematic and magnetic energy and appears to be the major driving factor in the evolution of these filaments on a global scale.

The Davis-Chandrasekhar-Fermi technique only describes the averaged global properties over the entire system. It is important to note that many physical parameters, such as densities however, the physical parameters, including densities, gas velocities, magnetic field strengths, etc., are far from being homogeneous but actually vary by orders of magnitudes in such a dynamical HFS. Therefore, an analysis merely focusing on the global aspect might lack information on spatial variations which is essential for us to understand how the physical condition evolves from the ambient material to the converging filaments, and to the central hub. Hence, we additionally developed an approach aiming at studying the detailed local interplay between the spatial properties of the filamentary structures, the magnetic fields, the local gravitational force, and the local velocity gradient.

As a first step to investigate the spatial properties, we performed an all-pairwise comparison of the relative orientation among filaments, magnetic fields, local gravitational force, and local velocity gradient on the dust continuum map (Figure 2). This comparison reveals systematic changes of these relative orientations from diffuse extending filaments toward the densest hub center. With statistics based on the Kolmogorov-Smirnov test, we conclude that the filaments tend to align with the magnetic field and local gravity in the dense hub. In the low-density areas, we find that the local velocity gradients tend to be perpendicular to both the magnetic field and local gravity, although the filaments still tend to align with local gravity.

Combining local and global aspects, we propose a scenario where G33.92+0.11 is a multiscale gravitationally collapsing cloud with relatively weak turbulence and magnetic field. The ambient gas in the diffuse environment is accreted onto the filaments, while the filaments drag the magnetic field lines and flow toward the gravitational center (illustrated in Figure 3). Due to the resolution limitation, the observed local velocity gradients mainly trace the gas accumulation from the surrounding to the filaments, especially in low-density areas, and are thus perpendicular to the filaments. The observed magnetic field is stretched by the accretion flows, especially in high-density areas, and is therefore aligned with filaments and gravity.

One challenge of this scenario is how these converging filaments remain stable without fragmenting into numerous cores before reaching the hub center. To answer this question, we estimate the variation of critical linear density along these filaments considering the support from both thermal, non-thermal, and magnetic support. We find that the non-thermal kinematic energy within these filaments, traced by the local velocity dispersion, is significantly increasing with the local density. In return, this can stabilize filaments from self-fragmenting until reaching the central hub. This mechanism might also explain how a massive star/protocluster can accumulate a significant amount of mass from the large-scale environment.

Figure 3: Cartoon illustrating observed features. The black arrows represent the directions of local gravity. The yellow curve shows a model-compatible magnetic field morphology, with the orange segments displaying the observed field segments with a spatial resolution (~0.5 pc) comparable to the filament widths (0.5–1 pc). The magenta arrows illustrate the directions of gas motion, with the white arrows depicting the observed velocity gradients at the resolved 0.5 pc scale. The background color displays local density. An outer subcritical and inner supercritical zone is indicated.

This research was published in The Astrophysical Journal at: https://iopscience.iop.org/article/10.3847/1538-4357/abc74e

Authors: Jia-Wei Wang1,2, Patrick M. Koch1, Roberto Galván-Madrid3, Shih-Ping Lai2, Hauyu Baobab Liu1, Sheng-Jun Lin2, and Kate Pattle2,4    

Edited by Steve Mairs

Author Affiliations:

1 Academia Sinica Institute of Astronomy and Astrophysics, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan

2 Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan; jwwang@asiaa.sinica.edu.tw

3 Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Apdo. Postal 3-72 (Xangari), 58089 Morelia, Michoacán, Mexico

4 Centre for Astronomy, School of Physics, National University of Ireland Galway, University Road, Galway, Ireland

Pōwehi: Astronomers Image Magnetic Fields at the Edge of M87’s Black Hole

Two Hawai`i-based telescopes, the James Clerk Maxwell Telescope (JCMT), operated by the East Asian Observatory, and the Submillimeter Array (SMA), operated by the Smithsonian Astrophysical Observatory and the Academia Sinica Institute for Astronomy and Astrophysics, have once again combined efforts with the global network of telescopes known as the Event Horizon Telescope. Today the image of Pōwehi, the Black Hole at the Centre of M87, has been shown in new light – specifically polarized light. The polarized light has enabled astronomers for the first time in history to measure polarization, a signature of magnetic fields, this close to the edge of a black hole. The observations are key to explaining how the M87 galaxy, located 55 million light-years away, is able to launch energetic jets from its core.

“We are now seeing the next crucial piece of evidence to understand how magnetic fields behave around black holes, and how activity in this very compact region of space can drive powerful jets that extend far beyond the galaxy,” says Monika Mościbrodzka, Coordinator of the EHT Polarimetry Working Group and Assistant Professor at Radboud University in the Netherlands.

On 10 April 2019, scientists released the first ever image of a black hole, Pōwehi, revealing a bright ring-like structure with a dark central region — the black hole’s shadow. Since then, the EHT collaboration has delved deeper into the data on the supermassive object at the heart of the M87 galaxy collected in 2017. They have discovered that a significant fraction of the light around the M87 black hole is polarized.

A view of the M87 supermassive black hole in polarized light. The Event Horizon Telescope (EHT) collaboration, who produced the first ever image of a black hole released in 2019, has today a new view of the massive object Pōwehi at the centre of the Messier 87 (M87) galaxy: how it looks in polarized light. This is the first time astronomers have been able to measure polarization, a signature of magnetic fields, this close to the edge of a black hole.This image shows the polarized view of the black hole in M87. The lines mark the orientation of polarization, which is related to the magnetic field around the shadow of the black hole. Credit: EHT

Light becomes polarized when it goes through certain filters. As an example many of us here in Hawai`i have polarized sunglasses, in space light can become polarized when it is emitted in hot regions of space that are magnetized. In the same way polarized sunglasses help us see better by reducing reflections and glare from bright surfaces, astronomers can sharpen their vision of the region around the black hole by looking at how the light originating from there is polarized. Specifically, polarization allows astronomers to map the magnetic field lines present at the inner edge of the black hole.

The bright jets of energy and matter that emerge from M87’s core and extend at least 5000 light-years from its centre are one of the galaxy’s most mysterious and energetic features. Most matter lying close to the edge of a black hole falls in. However, some of the surrounding particles escape moments before capture and are blown far out into space in the form of jets.

Hilo astronomer Geoff Bower who is the EHT Project Scientist said These beautiful images tell an amazing story of how powerful magnetic fields control the black hole’s appetite and funnel part of its lunch out at nearly the speed of light.  Producing these images was an incredible technical achievement from observations around the world to sophisticated image analysis.” 

Astronomers have relied on different models of how matter behaves near the black hole to better understand this process. But they still don’t know exactly how jets larger than the galaxy are launched from its central region, which is as small in size as the Solar System, nor how exactly matter falls into the black hole. With the new EHT image of the black hole and its shadow in polarized light, astronomers managed for the first time to look into the region just outside the black hole where this interplay between matter flowing in and being ejected out is happening.

This composite image shows three views of the central region of the Messier 87 (M87) galaxy in polarised light. The galaxy has a supermassive black hole at its centre and is famous for its jets, that extend far beyond the galaxy. One of the polarised-light images, obtained with the Chile-based Atacama Large Millimeter/submillimeter Array (ALMA), shows part of the jet in polarised light, with a size of 6000 light years from the centre of the galaxy. The other polarised light images zoom in closer to the supermassive black hole: the middle view covers a region about one light year in size and was obtained with the National Radio Astronomy Observatory’s Very Long Baseline Array (VLBA) in the US. The most zoomed-in view was obtained by linking eight telescopes around the world to create a virtual Earth-sized telescope, the Event Horizon Telescope or EHT. This allows astronomers to see very close to the supermassive black hole, into the region where the jets are launched. The lines mark the orientation of polarisation, which is related to the magnetic field in the regions imaged.The ALMA data provides a description of the magnetic field structure along the jet. Therefore the combined information from the EHT and ALMA allows astronomers to investigate the role of magnetic fields from the vicinity of the event horizon (as probed with the EHT on light-day scales) to far beyond the M87 galaxy along its powerful jets (as probed with ALMA on scales of thousand of light-years). The values in GHz refer to the frequencies of light at which the different observations were made. The horizontal lines show the scale (in light years) of each of the individual images. Credit: © EHT Collaboration; ALMA (ESO/NAOJ/NRAO), Goddi et al.; VLBA (NRAO), Kravchenko et al.; J. C. Algaba, I. Martí-Vidal

The team found that only 0.1% of the theoretical models can explain what the astronomers are seeing at the event horizon. The new observations also revealed information about the structure and strength of the magnetic field just outside the black hole that astronomers didn’t have before.

“Our first glimpse of Pōwehi – a snapshot of the total light intensity –  was like seeing the movie poster. Now, with our polarized glasses on, we have front row seats as the film begins. The polarized images show us how black holes do what they do and why we see what we see,”  JCMT Deputy Director, Dr Jessica Dempsey states. “Our worldwide and home team pushed every technical, theoretical and observational boundary to achieve this. And we are still in the first minutes of the story. We have so much more to see. Pass the popcorn.”

To observe the heart of the M87 galaxy, the collaboration linked eight telescopes around the world, including the JCMT and SMA located on Maunakea, to create a virtual Earth-sized telescope, the EHT. The impressive resolution obtained with the EHT is equivalent to that needed to measure the length of a credit card on the surface of the Moon.

This allowed the team to directly observe the black hole shadow and the ring of light around it, with the new polarized-light image clearly showing that the ring is magnetized.

“The EHT is a one-of-a-kind facility to test the laws of physics in a region of extreme gravity. It gives us a unique chance to look at phenomena we have never studied before,” says EHT collaboration member Jongho Park, an East Asian Core Observatories Association Fellow at the Academia Sinica, Institute of Astronomy and Astrophysics in Taiwan.

Future EHT observations will reveal even more information about the mysterious region of space near the event horizons of supermassive black holes.The results are published today in two separate papers in The Astrophysical Journal Letters by the EHT collaboration. The research, which was coordinated by Mościbrodzka, involved over 300 researchers from multiple organisations and universities worldwide. Simon Radford, Director of Hawaii Operations, Submillimeter Array said “This research showcases the close cooperation between observatories in Hawai’i and elsewhere. The SMA and the JCMT have participated in the EHT for more than a decade. They will continue to play a major role in future EHT observations because of their location, their technology, and the dedication of their talented staff.” 

Supplemental information

This research was presented in two papers published today in The Astrophysical Journal.

The Event Horizon Telescope

The EHT collaboration involves more than 300 researchers from Africa, Asia, Europe, North and South America. The international collaboration is working to capture the most detailed black hole images ever obtained by creating a virtual Earth-sized telescope. Supported by considerable international investment, the EHT links existing telescopes using novel systems — creating a fundamentally new instrument with the highest angular resolving power that has yet been achieved.

The individual telescopes involved are: ALMA, APEX, the IRAM 30-meter Telescope, the IRAM NOEMA Observatory, the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope (LMT), the Submillimeter Array (SMA), the Submillimeter Telescope (SMT), the South Pole Telescope (SPT), the Kitt Peak Telescope, and the Greenland Telescope (GLT).

The EHT consortium consists of 13 stakeholder institutes: the Academia Sinica Institute of Astronomy and Astrophysics, the University of Arizona, the University of Chicago, the East Asian Observatory, Goethe-Universitaet Frankfurt, Institut de Radioastronomie Millimétrique, Large Millimeter Telescope, Max Planck Institute for Radio Astronomy, MIT Haystack Observatory, National Astronomical Observatory of Japan, Perimeter Institute for Theoretical Physics, Radboud University and the Smithsonian Astrophysical Observatory.

Pōwehi

Astronomers collaborated with renowned Hawaiian language and cultural practitioner Dr. Larry Kimura for the Hawaiian naming of the supermassive black hole at the centre of the galaxy M87. Pōwehi, meaning embellished dark source of unending creation, is a name sourced from the Kumulipo, the primordial chant describing the creation of the Hawaiian universe. Pō, profound dark source of unending creation, is a concept emphasized and repeated in the Kumulipo, while wehi, or wehiwehi, honored with embellishments, is one of many descriptions of pō in the chant. Dr. Kimura is an associate professor at University of Hawai‘i at Hilo Ka Haka ‘Ula o Ke‘elikolani College of Hawaiian Language.

Media Contacts

Geoff Bower
Chief Scientist for Hawaii Operations, ASIAA
Project Scientist, Event Horizon Telescope
Affiliate Graduate Faculty, UH Manoa Physics and Astronomy
gbower@asiaa.sinica.edu.tw

 

Jessica Dempsey
Deputy Director of the East Asian Observatory (EAO) and JCMT
j.dempsey@eaobservatory.org

Local Media Coverage

JCMT and ALMA: Hunting for stellar nurseries in Orion

Stars are known to form in so-called “molecular clouds”; collections of cold gas and dust in the space between stars. These stellar nurseries can contain a number of dense clumps of gas and dust called “prestellar cores”. Research has suggested that these cores are expected to exhibit concentrated structures within them – the “seeds” of new stars right at the cusp of being born.

Strong efforts by astronomers have been made to find such “seeds” of stars inside prestellar cores in the past, but mostly in vain. It was difficult to catch such seeds in action perhaps because they are short-lived, but also due to the inherent difficulties in observing such dense regions and at such small scales. Despite the challenges, Dipen Sahu, at the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Taiwan, and lead author of this study stated that “despite the challenges it is very important to understand when and how such stellar embryo(s) come to live” noting that “it is this critical early stage that is important to observe as we understand how these early stages shape the stellar offspring. We would like to know how stellar systems are formed, but we need to study them near their birth to fully understand the process.”

We would like to know how stellar systems are formed, but we need to find them near their birth to understand the process.

One of the closest, brightest and most well known stellar nurseries can be found in the constellation of Orion also known as the Ka Hei-Hei O Nā Keiki (which refers to a children’s string game similar to the cat’s cradle) in Hawaiian. The international team, including astronomers from Taiwan, China, Japan, and Korea, first started out to uncover cold and dense cores in the Orion Molecular Cloud. As dust in the cores absorbs light and blocks the view at the optical wavelengths, astronomers make use of “light” emitted by the dust inside the dense cores at submillimeter wavelengths, obtained using such telescopes as the James Clark Maxwell Telescope (JCMT) situated on the slopes of Maunakea in Hawaii.

Core “G205.46-14.56M3” located in the Orion Molecular Cloud shows signs of multiple small blobs inside. Top right insert: SCUBA-2 image of G2-5.46-14.56M3 as observed by the JCMT, Hawaii. Bottom left insert: ALMA resolves the newly forming stars within. The Orion Constellation is also known as the Ka Hei-Hei O Nā Keiki (“the cat’s cradle”) in Hawaiian. Credit: ASIAA/Wei-Hao Wang/ALMA (ESO/NAOJ/NRAO)/Tie Lie/Sahu et al.

“The JCMT continues to play a pivotal role in locating these cores!”, says Tie Liu at Shanghai Astronomical Observatory, co-author of this study and the principal investigator of the ALMA observation program, “the JCMT is critical in that it gives us the speed to hunt around these stellar nurseries with the sensitivity needed to find these faint regions of cold and dense gas”.

With JCMT providing the team with stellar nursery candidates, the team turned to the largest telescope on the ground to date, the Atacama Large Millimeter and submillimeter Array (ALMA) located in the high desert in northern Chile. The observations carried out with ALMA in late 2018 to early 2019 unveil to the team five cores with  a very concentrated gas and dust distribution at a scale of a 1000 AU. Toward one core named “G205.46-14.56M3” in particular, the image shows signs of multiple small peak structures inside. These peaks are estimated to harbor a high density of cold gas that has never been seen before and their significant mass makes astronomers think that they are very likely to form a binary star system in the future. It is known that a large fraction of Sun-like stars are in binary or multiple stellar systems. Sheng-Yuan Liu at ASIAA, co-author of this study stated “ALMA provides us with unprecedented sensitivity and angular resolution so that we can see faint sources with truly sharp images. Finding twins or triplets should be common in stellar nurseries but it is remarkable to actually obtain the image like seeing inside an egg with two yolks!”

Finding twins or triplets should be common in stellar nurseries but it is remarkable to actually obtain the image like seeing inside an egg with two yolks!

It remains unclear what leads to the sub-structures we see in the core of G205.46-14.56M3. The substructures are likely a complicated interplay between the gas motion, gravity, and magnetic fields that are threading through the gas. The observed emission from the dust only tells us how gas and dust are distributed. Understanding how the gas is moving and how magnetic fields are distributed inside such cores would allow astronomers to further pinpoint the decisive process.

“Detecting such a handful of stellar seeds is just the beginning and the JCMT has proven to be a great tool for uncovering these nurseries. I am excited to see what new discoveries we will make when we combine the power of both JCMT and future followup studies with ALMA”, says Dipen Sahu.

The publication

This work was published: “ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Detection of Extremely High-density Compact Structure of Prestellar Cores and Multiple Substructures Within” by Dipen Sahu et al. in the Astrophysical Journal Letters.

The team is composed of Dipen Sahu (Academia Sinica Institute of Astronomy and Astrophysics), Sheng-Yuan Liu (Academia Sinica Institute of Astronomy and Astrophysics), Tie Liu (Shanghai Astronomical Observatory, Chinese Academy of Sciences), Neal J. Evans II (Department of Astronomy The University of Texas at Austin), Naomi Hirano (Academia Sinica Institute of Astronomy and Astrophysics), Ken’ichi Tatematsu (Nobeyama Radio Observatory, National Astronomical Observatory of Japan, National Institutes of Natural Sciences), Chin-Fei Lee(Academia Sinica Institute of Astronomy and Astrophysics), Kee-Tae Kim (Korea Astronomy and Space Science Institute), Somnath Dutta (Academia Sinica Institute of Astronomy and Astrophysics), Dana Alina (Department of Physics, School of Sciences and Humanities, Nazarbayev University)

Contact Information

Dr. Sheng-Yuan Liu
Academia Sinica Institute of Astronomy and Astrophysics
ASIAA, Taiwan
Email: syliu@asiaa.sinica.edu.tw

Dr. Jessica Dempsey
James Clerk Maxwell Telescope
East Asian Observatory, Hawaii, USA
Email: ​j.dempsey@eaobservatory.org

Media Releases:

  • Media release at ASIAA
  • Media release at SHAO
  • Media release at NAOJ

JCMT Astronomer helps size up the first black hole ever detected

Dr. Alex Tetarenko, a Hilo based astronomer who works at the James Clerk Maxwell Telescope (JCMT), has been collaborating with an international team of researchers to analyze new observations of the first black hole ever detected. Their discovery is leading astronomers to question what they know about the Universe’s most mysterious objects.

Dr. Alex Tetarenko, Credit: EAO

Published today in the journal Science, the research shows that the system known as Cygnus X-1, contains the most massive stellar-mass black hole ever detected without the use of gravitational waves. “Our new observations have shown us that Cygnus X-1 is further away from Earth than previously thought, which in turn tells us this black hole is much larger than previous estimates, weighing in at more than 20 times the mass of our own Sun” says Dr. Tetarenko.

 

The Cygnus X-1 binary system consists of a stellar-mass black hole that is pulling material off of a ‘donor star’. “Our new observations have shown us that Cygnus X-1 is further away from Earth than previously thought, which in turn tells us the black hole is much larger than previous estimates, weighing in at more than 20 times the mass of our own Sun.” Artist: Pete Wheeler (COMET) Credit: International Centre for Radio Astronomy Research.

Cygnus X-1 is one of the closest black holes to Earth. It was discovered in 1964 when a pair of Geiger counters were carried on board a sub-orbital rocket launched from New Mexico. This object was famously the focus of a scientific wager between physicists Stephen Hawking and Kip Thorne, with Hawking betting in 1974 that it was not a black hole and eventually conceding the bet in 1990.

In this latest work, astronomers observed a full orbit of the black hole over a six day period using the Very Long Baseline Array — a continent-sized radio telescope made up of 10 dishes spread across the United States — together with a clever technique to measure distances in space. “One of the telescopes in the Very Long Baseline Array is located in Hawaiʻi on the slopes of Maunakea, and this antenna plays a critical role in making it possible to do this kind of science” explains Dr. Tetarenko.

Lead researcher, Professor James-Miller Jones from Curtin University and the International Centre for Radio Astronomy Research (ICRAR) outlines the clever technique used by this team of researchers. “If we can view the same object from different locations, we can calculate its distance away from us by measuring how far the object appears to move relative to the background. If you hold your finger out in front of your eyes and view it with one eye at a time, you’ll notice your finger appears to jump from one spot to another. It’s exactly the same principle.”

“The domino effect of our new observations has led to fascinating new insights about how stars evolve and how black holes form” says co-author Dr. Arash Bahramian, who is also at Curtin University and ICRAR. Tetarenko and Bahramian are longtime colleagues, having both completed their PhDs at the University of Alberta in Canada.

In fact, this study has sparked two more companion papers. Co-author Professor Ilya Mandel from Monash University and the ARC Centre of Excellence in Gravitational Wave Discovery (OzGrav) further explains the wide reaching implications of this work.

“Cygnus X-1 in particular began life as a star approximately 60 times the mass of the Sun and collapsed tens of thousands of years ago. During their lifetime stars lose mass to their surrounding environment through stellar winds that blow away from their surface. But to make a black hole as heavy as Cygnus X-1, we need to dial down the amount of mass that bright stars lose during their lifetimes”.

The new measurements of distance and mass also tell us that the black hole in Cygnus X-1 is spinning incredibly quickly (very close to the speed of light), as shown in a second companion paper led by PhD candidate, Xueshan Zhao, at the Chinese Academy of Sciences.

“All of these exciting discoveries were made possible by the collaboration between a diverse group of international astronomers focused on different observational and theoretical aspects of black holes, all coming together for a new extensive and rigorous look at a known but previously elusive black hole.” adds Dr. Bahramian.

As the next generation of telescopes comes online, their improved sensitivity reveals the Universe in increasingly more detail, leveraging decades of effort invested by scientists and research teams around the world to better understand the cosmos and the exotic and extreme objects that exist.

“Studying black holes is like shining a light on the Universe’s best kept secret—it’s a challenging but incredibly exciting area of research” says Professor Miller-Jones. “There is so much left to discover about these enigmatic astrophysical objects” adds Dr. Tetarenko.

 

Original Publication:
‘Cygnus X-1 contains a 21-solar mass black hole – implications for massive star winds’, published in Science on February 18th, 2021.

Companion Papers:
‘Reestimating the Spin Parameter of the Black Hole in Cygnus X-1’, published in The Astrophysical Journal on February 18th, 2021.

‘Wind mass-loss rates of stripped stars inferred from Cygnus X-1’, published in The Astrophysical Journal on February 18th, 2021.

Contacts:

Dr. Alex Tetarenko, EAO Fellow, East Asian Observatory
a.tetarenko@eaobservatory.org

Dr. Jessica Dempsey, Deputy Director of the East Asian Observatory (EAO) and JCMT
j.dempsey@eaobservatory.org

 

Local Media Coverage

Call for Proposals 21B

PLEASE NOTE THAT THIS CALL FOR PROPOSALS HAS NOW CLOSED.

 

The East Asian Observatory is happy to invite PI observing proposals for semester 21B at the JCMT. Proposal submission is via the JCMT proposal handling system, Hedwig. For full details, and for proposal submission, please see

https://proposals.eaobservatory.org/

The 21B Call for Proposals closes on the 16th of March, 2021.

If this is your first time using Hedwig, you should ‘Log in’ and generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.

Please contact us at helpdesk@eaobservatory.org if you have remaining questions.

First Light with new JCMT receiver `Āweoweo

IRC+10216, also known as CW Leonis – a carbon star embedded in a thick dust envelope, was the target for first light observations with the second Nāmakanui insert; `Āweoweo. This spectrum was captured on the night of January 13 2021 (UT 20200114).

`Āweoweo operates between 283 – 365 GHz and is a Sideband Separating (2SB) instrument. When commissioned, `Āweoweo, will be available to both JCMT Users (PI and Large Programs – perfect for sensitive single pointing observations), and VLBI users (as part of the Event Horizon Telescope and the East Asian VLBI Network).

JCMT staff presented “Commissioning of Nāmakanui on the JCMT” at the SPIE conference in December 2020. For details see: Mizuno et al. 2020.

SCUBA-2 captures Jupiter and Saturn Conjunction

JCMT astronomers were excited to capture the conjunction of Saturn and Jupiter on December 21st 2020 using SCUBA-2. The conjunction – although occurring every 20 years the closest one prior to 2020 was in 1623 and this won’t be matched again until the Jupiter-Saturn conjunction of March 15, 2080. Telescope operator Kevin Silva was on hand to capture this unique moment.

Aside from science, the telescope operators at JCMT do use Jupiter or Saturn for focusing, and occasionally Saturn for pointing. Dr Harriet Parsons was interviewed by Hawaii News Now about the event.

Jupiter and Saturn as observed by SCUBA-2 at a wavelength of 0.85mm. Remember we are not seeing our Sun’s light reflected off the planets, what we are seeing is the planet “glowing” thermally in submillimeter, similar to how the volcanologists monitor Halema`uma`u crate at night – the active volcano on Hawai`i. Jupiter we see is much brighter than Saturn, larger in angular extent. Saturn is slightly elongated – thanks to Saturn’s rings.

Jupiter and Saturn are so bright that we have a harder time seeing the fainter moons of Jupiter. In this resealed image we get to see Callisto, the moon of Jupiter approximately 3.8′ out from Jupiter. The Spikes we see around Jupiter is artificial – they are diffraction spikes caused by light bending/diffracting around the support beams of our secondary mirror. The brighter circles around Jupiter and Saturn are also artificial – they are caused from the sheer brightness of the planets.

 

JCMT Semester 21A Proposal Review Timeline Update

Due to an exceptional combination of contributing factors this year, the JCMT TAC Meeting for Semester 21A is now expected to take place on January 20th – 22nd, 2021. As this is much closer to the start of the new semester than usual, JCMT users that have submitted proposals targeting the semester 21A observing period should please bear in mind that, in the event that their proposal proves successful, the pre-semester window of opportunity for the upload of MSBs will be shorter than usual. In particular, proposers with astronomical target objects already observable in early-mid February may wish to plan ahead accordingly.

Special Supplementary Call for Canada-led Proposals (21A)

PLEASE NOTE THAT THIS CALL FOR PROPOSALS HAS NOW CLOSED.

 

The East Asian Observatory is pleased to invite JCMT observing proposals with Principal Investigators (PIs) affiliated with Canadian institutions only for a special 21A Supplementary Call for Proposals. Proposal submission is via the JCMT proposal handling system, Hedwig. For full details, and for proposal submission, please see here.

The proposal submission deadline for this Special 21A Supplementary Call for Proposals is 2020-10-29 22:00 UTC.

This Call offers time for two Canadian JCMT user communities:

  1. A Canadian JCMT Consortium, consisting of the following institutions: McMaster University, Queen’s University, University of Alberta, University of Manitoba, University of Montreal;
  2. All Canada-based institutions, including those listed above.

Proposals with PIs from the first above group are eligible for any of the available Canadian JCMT time available in semester 21A. Proposals with PIs from all other Canadian institutions are eligible to apply for the fraction of the Canadian JCMT time available in 21A that is funded at the national level (by ACURA and NRC-HAA).

If this is your first time using Hedwig, you should ‘Log in’ and generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.

Please contact us at helpdesk@eaobservatory.org if you have remaining questions.

Special Supplementary Call for South Korea-led Proposals (21A)

PLEASE NOTE THAT THIS CALL FOR PROPOSALS HAS NOW CLOSED.

 

The East Asian Observatory invites JCMT observing proposals with Principal Investigators (PIs) affiliated with a South Korean institution only for a special 21A Supplementary Call for Proposals. Proposal submission is via the JCMT proposal handling system, Hedwig. For full details, and for proposal submission, please see here.

The proposal submission deadline for this Special 21A Supplementary Call for Proposals is 2020-11-19 22:00 UTC.

If this is your first time using Hedwig, you should ‘Log in’ and generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.

Please contact us at helpdesk@eaobservatory.org if you have remaining questions.

JCMT finds hints of life on Venus

An international team of astronomers, led by Professor Jane Greaves of Cardiff University, UK, today announced the discovery of a rare molecule – phosphine – in the clouds of Venus. On Earth, this gas is only made industrially, or by microbes that thrive in oxygen-free environments. The detection of phosphine could point to such extra-terrestrial “aerial” life. “When we got the first hints of phosphine in Venus’s spectrum, it was a shock!”, said Jane, who first spotted signs of phosphine in observations from the James Clerk Maxwell Telescope (JCMT) in Hawai`i.

Astronomers have speculated for decades that high clouds on Venus could offer a home for microbes – floating free of the scorching surface, with access to water and sunlight, but needing to tolerate very high acidity. The detection of phosphine, which consists of hydrogen and phosphorus, could point to this extra-terrestrial ‘aerial’ life. The new discovery is described in a paper published today in Nature Astronomy.

Artistic impression of Venus depicting a representation of phosphine molecule shown in the inset. The molecules were detected in the Venusian high clouds in data from the James Clerk Maxwell Telescope and the Atacama Large Millimeter/submillimeter Array. Astronomers have speculated for decades that life could exist in Venus’s high clouds. The detection of phosphine could point to such extra-terrestrial “aerial” life. Image credit: ESO/M. Kornmesser/L. Calçada & NASA/JPL/Caltech.

The first detection of phosphine in the clouds of Venus was made using the JCMT in Hawai`i. The team were then awarded time to follow up their discovery with 45 telescopes of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. Both facilities observed Venus at a wavelength of about 1 millimetre, much longer than the human eye can see – only telescopes at high altitude can detect it effectively. “In the end, we found that both observatories had seen the same thing — faint absorption at the right wavelength to be phosphine gas, where the molecules are backlit by the warmer clouds below” said Jane.

The astronomers then ran calculations to see if the phosphine could come from natural processes on Venus. Massachusetts Institute of Technology scientist Dr William Bains led the work on assessing natural ways to make phosphine. Some ideas included sunlight, minerals blown upwards from the surface, volcanoes, or lightning, but none of these could make anywhere near enough of it. Natural sources were found to make at most one ten thousandth of the amount of phosphine that the telescopes saw. In contrast the team found that in order to create the observed quantity of phosphine on Venus, terrestrial organisms would only need to work at about 10% of their maximum productivity. Any microbes on Venus will though likely be very different to their Earth cousins. Earth bacteria can absorb phosphate minerals, add hydrogen, and ultimately expel phosphine gas.

Team member and MIT researcher, Dr Clara Sousa Silva, had thought about searching for phosphine as a ‘biosignature’ gas of non-oxygen-using life on planets around other stars, because normal chemistry makes so little of it. She comments “Finding phosphine on Venus was an unexpected bonus! The discovery raises many questions, such as how any organisms could survive. On Earth, some microbes can cope with up to about 5% of acid in their environment – but the clouds of Venus are almost entirely made of acid.

The team believes this discovery is significant because they can rule out many alternative ways to make phosphine, but they acknowledge that confirming the presence of “life” needs a lot more work. Although the high clouds of Venus have temperatures up to a pleasant 30 degrees centigrade, they are incredibly acidic – around 90% sulphuric acid – posing major issues for microbes to survive there. Prof Sara Seager and Dr Janusz Petkowski, both at MIT, are investigating how microbes could shield themselves inside scarce water droplets.

The team are now eagerly awaiting more telescope time to establish whether the phosphine is in a relatively temperate part of the clouds, and to look for other gases associated with life. This result also has implications in the search for life outside our Solar system.

On hearing the results of the JCMT study, the JCMT’s Deputy Director Dr Jessica Dempsey said “These results are incredible” and went on to say “this discovery made in Hawai`i, by the JCMT, was made with a single pixel instrument. This is the very same instrument that also took part in capturing the first image of a Black Hole, Pōwehi. The discovery of phosphine in the atmosphere of Venus really showcases the breadth of cutting-edge research undertaken by astronomers using the JCMT. I am so pleased of the efforts from all our staff here in Hawai`i

JCMT, seen with its white iconic Gore-Tex membrane, open for morning observing. The shadow of Maunakea rises over Hualālai in the distance. JCMT is able to observe during the daytime as it operates at sub-millimeter wavelengths. Image credit: Tom Kerr, UKIRT.

Former UH Hilo astronomy student, E’Lisa Lee who took some of the JCMT data during her time working as a part-time JCMT telescope operator summed up her feelings “An observed biochemical process occurring on anything other than Earth has the greatest and most profound implications for our understanding of life on Earth, and life as a concept.” Adding “Being able to participate in the scientific process, as an operator at JCMT was an incredible and humbling experience. It is my sincerest hope that further observations will allow for greater exploration of Venusian clouds and everything beyond.” E’Lisa currently studying for her Master’s degree in physics at Fresno State University.

The JCMT instrument that captured this phosphine discovery has since retired and been replaced by a new and more sensitive instrument known as Nāmakanui. On the potential of this new instrument, Jessica commented “Like it’s namesake, the big-eyed fish hunting food in the dark waters, we will turn the far more sensitive Nāmakanui back to Venus in this hunt for life in our universe.  This is just the beginning, and I’ve never been more excited to be a part of our boundary-pushing JCMT team.”

JCMT Deputy Director, Jessica Dempsey stands beside the now retired instrument, RxA3m, that made this first detection of phosphine on Venus. The instrument has since been replaced by a more powerful instrument called Nāmakanui. Image Credit: Harriet Parsons.

Supplemental Information

This research was presented in the paper “Phosphine Gas in the Cloud Decks of Venus” published in Nature Astronomy. A copy of the paper will be available with free access from www.nature.com/articles/s41550-020-1174-4. Further information and resources can be found at: maunakeaobservatories.org/venusnews/

Video assets and additional information available on the Maunakea Observatories website.

Previous papers discussing the nature of phosphine and life on Venus:

The team is composed of: Jane S. Greaves (Cardiff University, UK), Anita M. S. Richards (Jodrell Bank Centre for Astrophysics, The University of Manchester, UK), William Bains (MIT, USA), Paul Rimmer (Department of Earth Sciences and Cavendish Astrophysics, University of Cambridge and MRC Laboratory of Molecular Biology, Cambridge, UK), Hideo Sagawa (Kyoto Sangyo University, Japan), David L. Clements (Imperial College London, UK), Sara Seager (MIT, USA), Janusz J. Petkowski (MIT, USA), Clara Sousa-Silva (MIT), Sukrit Ranjan (MIT), Emily Drabek-Maunder (Cardiff and Royal Observatory Greenwich, UK), Helen J. Fraser (The Open University, UK), Annabel Cartwright (Cardiff University, UK), Ingo Mueller-Wodarg (Imperial College, UK), Zhuchang Zhan (MIT, USA), Per Friberg (EAO/JCMT), Iain Coulson (EAO/JCMT), E’Lisa Lee (EAO/JCMT) and Jim Hoge (EAO/JCMT).

The authors of the paper. Find more of the discussion on social media by following the #VenusNews

`Ōlelo Hawai`i

A copy on the Press Release in `ōlelo Hawai`i is provided here.

Makaola

Dr. Larry Kimura, Associate Professor University of Hawaii, Hilo in the Ka Haka ʻUla O Keʻelikōlani, College of Hawaiian Language was asked to provide assistance with the translation of the news of the detection of phosphine into `ōlelo Hawai`i. The translatio required Dr Kimura to create a new word to describe the possibility of the detection of life. In the process Makaola – a detection of life – was formed.

Maka is the basic word for “eye” and in Hawaiian the nuances or other meanings go on; kūmaka-visible, seen; makaʻala-alert, watchful; makamua-the very first; etc.  Also as used in the Kumulipo when we see “maka liʻi” or tiny eyes, those maka are tiny dots so other meanings for maka are a point of beginning, or like the tip of a pen or spear.  It is the word we use to mean to begin with the causative marker “hoʻo” or hoʻomaka. Ola is the word for life, alive, living, and support.

JCMT – The James Clerk Maxwell Telescope

With a diameter of 15m (50 feet) the James Clerk Maxwell Telescope (JCMT) is the largest single dish astronomical telescope in the world designed specifically to operate in the submillimetre wavelength region of the electromagnetic spectrum. The JCMT is used to study our Solar System, interstellar and circumstellar dust and gas, evolved stars, and distant galaxies. It is situated in the science reserve of Maunakea, Hawai`i, at an altitude of 4092m (13,425 feet).

The JCMT is operated by the East Asian Observatory on behalf of CAMS (NAOC, PMO, and SHAO); NAOJ; ASIAA; KASI; as well as the National Key R&D Program of China. Additional funding support is provided by the STFC and participating universities in the UK and Canada​.

Nāmakanui was constructed and funded by ASIAA, with funding for the mixers provided by ASIAA and at 230GHz by EAO. The Nāmakanui instrument is a backup receiver for the GLT.

ALMA – The Atacama Large Millimeter/submillimeter Array

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council (NSC) and by NINS in cooperation with the Academia Sinica (AS) and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

Media Contact

Dr. Jessica Dempsey
James Clerk Maxwell Telescope, East Asian Observatory
Email: j.dempsey@eaobservatory.org

Dr Jane Greaves
Cardiff University
Email: GreavesJ1@cardiff.ac.uk

Call for Proposals 21A

PLEASE NOTE THAT THIS CALL FOR PROPOSALS HAS NOW CLOSED.

The East Asian Observatory is happy to invite PI observing proposals for semester 21A at the JCMT. Proposal submission is via the JCMT proposal handling system, Hedwig. For full details, and for proposal submission, please see

The East Asian Observatory is happy to invite PI observing proposals for semester 21A at the JCMT. Proposal submission is via the JCMT proposal handling system, Hedwig. For full details, and for proposal submission, please see

https://proposals.eaobservatory.org/

The 21A Call for Proposals closes on the 16th of September, 2020.

If this is your first time using Hedwig, you should ‘Log in’ and generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.

Please contact us at helpdesk@eaobservatory.org if you have remaining questions.

JCMT survey reveals “treasure map” for star formation

The JCMT SCOPE Survey has provided astronomers studying the formation of stars a treasure map for follow up observations by the Nobeyama 45-m radio telescope and ALMA to reveal the treasures within. Two such treasures include an image of a multiple star system on the cusp of formation alongside a rare glimpse of a baby star heating up its surrounding material making its womb glow like a pair of eyes. These results were published in a number of papers produced this week in the Astrophysical Journal. 

Dr. Tie Liu, Shanghai astronomer – and until last summer – a visiting researcher in Hilo Hawai`i has been hunting baby stars for over a decade. He is the Principle Investigator of the JCMT SCOPE survey that observed over 3,500 sites where stars were believed to be on the cusp of formation within the Milky Way, these sites are known to be dense cores. The dense cores are “a treasure trove for astronomers investigating the very early phases of star formation” said Tie Liu when asked about the survey, noting that “It’s great that we have powerful tools such as ALMA but ALMA has such a small field of view you need a telescope like JCMT to know where to look!

Figure 1. Top: image of the JCMT with the Orion constellation highlighted (image credit William Montgomerie). Middle: N2H+ maps obtained with the Nobeyama telescope with 850 micon JCMT/SCUBA-2 contours overlaid. In the Middle image the team identified a number of dense cores. Bottom: The ALMA-Morita Array reveals two different substructures within each dense core. Bottom left: multiple stars are seen being formed in the early starless core phase (source G211). Bottom right: a mysterious pair of eyes appear to peer out from the disk around the newly forming star – these highlight rich chemistry occurring in the disk of this newly forming star (Results presented in Tatematsu et al. 2020).

Taking advantage of the JCMT treasure map of dense cores produced by the JCMT SCOPE team is an international research team lead by Gwanjeong Kim and Ken Tatematsu of the Nobeyama Radio Observatory (NRO), Japan. The team have observed over of the 200 dense cores, with the NRO 45-m radio telescope and the Morita Array, which is the East-Asian constructed part of the world’s most powerful radio telescope ALMA.

When discussing the chosen cores to observe with ALMA, Ken Tatematsu, director of NRO and the co-PI of the SCOPE project in Japan stated “We are able to locate exact places for near-future star formation, by using the fact that the deuterium percentage reaches its maximum just at the time of star formation”. Deuterium, which is a special kind of hydrogen, was carefully measured by the team in over 100 cores located in the Orion constellation,with the Nobeyama-45m radio Telescope.

The two rare finds discovered by the team are shown in Figure 1. An image of a multiple star system on the cusp of formation and a glimpse of a baby star heating up its surrounding material making its womb glow like a pair of eyes. Ken Tatematsu said  “what’s exciting is that in the pseudo-disk of the dense core G210, we see these two bright eyes staring back at us – this is the region around the baby star being heated and undergoing a chemical change. Usually such detail is hidden from view, but not anymore!

As to the question why this is such a great find, co-author on this work Tie Liu noted that “from the chemical models such examples as we have found should be quite common, but without the resolution we cannot see the structure. JCMT is the perfect telescope for finding such candidates but we do then need to draw on the power of a telescope such as ALMA”.

These results give us important clues to understand how stars start to form. Commenting on the future of this work Tie Liu said “We will do more systematic studies of these SCOPE dense cores with high resolution interferometric observations (e.g. ALMA), who knows what other treasures will be found”.This work has been published in the following three papers:

  1. Tatematsu et al. 2020 “ALMA ACA and Nobeyama Observations of Two Orion Cores in Deuterated Molecular Lines
  2. Kim et al. 2020 “Molecular Cloud Cores with High Deuterium Fraction: Nobeyama Single-Pointing Survey

Supplementary Information

With a diameter of 15m (50 feet) the James Clerk Maxwell Telescope (JCMT) is the largest astronomical telescope in the world designed specifically to operate in the submillimetre wavelength region of the electromagnetic spectrum. The JCMT is used to study our Solar System, interstellar and circumstellar dust and gas, evolved stars, and distant galaxies. It is situated in the science reserve of Maunakea, Hawai`i, at an altitude of 4092m (13,425 feet).

The JCMT is operated by the East Asian Observatory on behalf of NAOJ; ASIAA; KASI; CAMS as well as the National Key R&D Program of China. Additional funding support is provided by the STFC and participating universities in the UK and Canada​. Supplementary Information about SCUBA-2:

The James Clerk Maxwell Telescope (JCMT) observations were obtained using the “Submillimetre Common User Bolometer Array 2”, a specialized camera known by its acronym, SCUBA-2. SCUBA-2 consists of 10,000 superconducting Transition Edge Sensor (TES) bolometers that allow for simultaneous observations at wavelengths of 450 and 850 microns. Scientists regularly use SCUBA-2 to observe star-forming regions and other astronomical regions and phenomenon.

Supplementary Information about the JCMT SCOPE survey:

Contact Information:

Dr. Tie Liu
Shanghai Observatory
Email: liutie@shao.ac.cn

Dr. Harriet Parsons,
East Asian Observatory, JCMT
Email: h.parsons@eaobservatory.org

 

“Starspots” on Betelgeuse: JCMT Explains Star’s Record-Breaking Dimming

New data obtained using the Hawai`i-based James Clerk Maxwell Telescope (JCMT) revealed that the surface of Betelgeuse (commonly known as Orion’s shoulder), recently developed significant “Starspots” which caused an unprecedented dimming of the star. This result contrasts the previously accepted explanation that the reduction in brightness was due to a veil of newly created dust that obscured the star. The research was published today in the prestigious Astrophysical Journal Letters.

An artist’s rendering of Betelgeuse, Dr. Thavisha Dharmawardena from the Max Planck Institute for Astronomy, and Dr. Steve Mairs from the James Clerk Maxwell Telescope

Beginning in October, 2019, the Red Supergiant star, Betelgeuse, experienced a record-breaking dimming event where it became three times fainter than usual. This phenomenon captured the interest of both professional astronomers and the public, largely fuelled by curiosity in the red supergiant’s demise and whether this change in brightness was heralding an imminent supernova explosion. In an anti-climactic conclusion, however, the star eventually increased in brightness again to its regular appearance. The explanation that emerged at the time was that the dimming was caused by a newly formed cloud of dust that blocked some of the light before it reached our telescopes here on Earth. An independent study led by Dr. Thavisha Dharmawardena, postdoctoral researcher at the Max Planck Institute for Astronomy, Germany, and Dr. Steve Mairs, Senior Scientist at the James Clerk Maxwell Telescope, Hawai`i, USA, however, offers the more likely explanation that the surface of Betelgeuse itself underwent a significant change.

Like tuning to a different radio station in a car, telescopes are each tuned to observe different types of light. In this way, observations from different telescopes can be combined to help fill in the whole picture. “​By using the James Clerk Maxwell Telescope here in Hawai`i, we were able to collect a type of light called ‘submillimetre light’ that is not visible to the human eye,”​ Mairs explains, “​This provided the crucial information that allowed us to conclude that there was no dust in the way; Betelgeuse was feeling shy with a face full of spots.”​

An artist’s impression of the Red Supergiant Betelgeuse. Its surface is covered by large starspots, which reduce its brightness. During their pulsations, such stars regularly release gas into their surroundings, which condenses into dust. (Image: Graphics Department/MPIA).

New JCMT images were obtained in January, February, and March, 2020 while Betelgeuse was faint and they were compared with observations taken over the past 13 years. These previous observations include images obtained by the Atacama Pathfinder Experiment (APEX), a telescope in Chile that observes the same type of light as the JCMT. “​What surprised us was that Betelgeuse turned 20% darker during its dimming event even in submillimetre light,”​ Dharmawardena says “​This behaviour is not at all compatible with the presence of dust. It was very exciting to realise that the star itself had undergone this massive change​”.

According to the scientists, the simultaneous darkening in visible and submillimetre light is evidence for a reduction in the mean surface temperature of Betelgeuse by 200 °C (360 °F). ​“However, an asymmetric temperature distribution is more likely,”​ Dharmawardena explains, referring to corresponding high-resolution images of Betelgeuse from December 2019 that depict an uneven distribution of stellar brightness.​ “Together with our result, this is a clear indication of huge starspots covering between 50 and 70% of the visible surface, each having a lower temperature than the rest of the surface.”​ Starspots, similar to sunspots, are common in giant stars, but not on this scale. Not much is known about their lifetime. However, theoretical model calculations seem to be compatible with the duration of Betelgeuse’s dip in brightness.

The team will continue to track the brightness of Betelgeuse with the JCMT over the next year to uncover more details about how the star is physically changing over different timescales. ​“Previous generations of stars like Betelgeuse have physically manufactured most of the elements we find on Earth and indeed in our bodies, distributing them throughout the Galaxy in massive supernova explosions.”​ Mairs explains. ​“While we cannot predict when the star will explode, tracking its brightness will allow us not only to better understand the evolution of an interesting class of stars, but it also helps write a page in our own cosmic story.”

——-

Supplementary information about Betelgeuse:

Betelgeuse, known as Kauluakoko in `ōlelo Hawaii, is the nearest red supergiant star to the Earth at a distance of only 500 light years. It is the red shoulder of the constellation Orion. It is so large that if Betelgeuse were to be placed at the location of our Sun, Mercury, Venus, the Earth, Mars, and the asteroid belt, would all be contained inside the star. With such a close proximity, it acts as a unique laboratory to aid in the understanding of the late stages of red supergiant evolution. Massive stars (Betelgeuse is 11 times heavier than our Sun) are important to study as they are the main drivers of chemical evolution in the universe. Stars like Betelgeuse manufacture many of the elements that comprise our bodies and our planet and even before the explosive end of their lives, massive stars undergo episodes wherein they lose material, enriching their surroundings with newly formed chemical elements. These periods of mass loss are accompanied by pulsations with periods of up to a few years.

Supplementary Information about the JCMT:

With a diameter of 15m (50 feet) the James Clerk Maxwell Telescope (JCMT) is the largest astronomical telescope in the world designed specifically to operate in the submillimetre wavelength region of the electromagnetic spectrum. The JCMT is used to study our Solar System, interstellar and circumstellar dust and gas, evolved stars, and distant galaxies. It is situated in the science reserve of Maunakea, Hawai`i, at an altitude of 4092m (13,425 feet).

The JCMT is operated by the East Asian Observatory on behalf of NAOJ; ASIAA; KASI; CAMS as well as the National Key R&D Program of China. Additional funding support is provided by the STFC and participating universities in the UK and Canada​. Supplementary Information about SCUBA-2:

The James Clerk Maxwell Telescope (JCMT) observations were obtained using the “Submillimetre Common User Bolometer Array 2”, a specialised camera known by its acronym, SCUBA-2. SCUBA-2 consists of 10,000 superconducting Transition Edge Sensor (TES) bolometers that allow for simultaneous observations at wavelengths of 450 and 850 microns. Scientists regularly use SCUBA-2 to observe star-forming regions, Red Giant stars, and the most distant galaxies ever discovered. At an operating temperature of -459.5 degrees fahrenheit, SCUBA-2 at the JCMT is one of the coldest places in the known Universe.

Contact Information:

Dr. Thavisha Dharmawardena
Max Planck Institute for Astronomy
Email: ​dharmawardena@mpia.de

Dr. Steve Mairs
James Clerk Maxwell Telescope
East Asian Observatory
Email: ​s.mairs@eaobservatory.org

Dr. Jessica Dempsey
James Clerk Maxwell Telescope
East Asian Observatory
Email: ​j.dempsey@eaobservatory.org

JCMT Telescope Operator Featured on CBS “Mission Unstoppable”

JCMT Telescope System Specialist Mimi Fuchs is on the front page of the Hawaii Tribune-Herald  today showcasing her appearance in an episode of “Mission Unstoppable” on CBS. As well as being an operator at the JCMT Mimi is an IF/THEN Ambassador for the AAAS – The American Association for the Advancement of Science.

Read the full Hawaii Tribune-Herald article here.

Watch the “Mission Unstoppable” segment here.

The Event Horizon Telescope brings the world together to observe new mysteries in quasar 3C 279

First Event Horizon Telescope Observations of a Black-Hole Powered Jet announced as Maunakea Observatories offer MKO@Home online resources

Two Hawai’i-based telescopes, the James Clerk Maxwell Telescope (JCMT), operated by the East Asian Observatory, and the Submillimeter Array (SMA), operated by the Smithsonian Astrophysical Observatory and the Academia Sinica Institute for Astronomy and Astrophysics, have once again provided crucial information in the global effort to understand Black Holes. The JCMT and SMA linked up with six other telescopes around the world to form the Event Horizon Telescope (EHT), in an effort involving hundreds of astronomers and engineers. The black hole targeted in these observations resides at the centre of a galaxy called 3C 279. This galaxy is 5 billion light years away in the direction of the Virgo constellation.

Nearly one year ago, the JCMT and the SMA played a vital role in the groundbreaking EHT observational campaign to observe the very first image of a black hole, which was given the Hawaiian name Pōwehi. The EHT collaboration is excited to announce this new result from data obtained at the same time as the Pōwehi result.

For the first time, astronomers have observed a jet travelling at close to the speed of light, that is believed to originate from the vicinity of a supermassive black hole, in unprecedented detail. In their analysis, led by astronomer Jae-Young Kim from the Max Planck Institute for Radio Astronomy in Bonn (MPIfR), the collaboration studied the exquisite detail of the jet’s shape close to the base. The jet base is a fascinating region where highly variable, high energy gamma-ray emission is thought to originate.

The results will be published in the coming issue of the prestigious journal ​Astronomy & Astrophysics​.

 

Fig. 1: Illustration of 3C 279 jet structure in April 2017. The observing epochs, arrays, and frequencies are noted at the top of each panel. Credit: J.Y. Kim (MPIfR) & the Event Horizon Telescope Collaboration

 

The black hole targeted in these observations is called 3C 279. It resides at the centre of a galaxy 5 billion light years away in the direction of the constellation Virgo. Scientists classify this galaxy as a quasar because it shines ultra-bright and flickers, signifying that massive amounts of gases and stars are falling into the giant black hole at the centre. The black hole in 3C 279 is about one billion times the mass of our own sun. Any material such as stars, gas, or dust that comes close to this black hole is shredded by strong gravitational forces, causing a large donut-shaped structure known as an accretion disc to form around the object. But not all of this shredded material stays in the accretion disc or ends up falling into the Super Massive Black Hole. Some of the material will be squirted back out into space in two fine fire-hose-like jets of plasma, travelling at speeds near the speed of light. These jets are powerful and demonstrate the enormous forces at play in the centre of this galaxy.

Through linking up many telescopes across the globe, using a technique known as very long baseline interferometry (VLBI), the astronomers are able to see the jet and accretion disc in action, distinguishing the sharpest-ever details in the jet. The new jet images, probing size scales finer than a light-year, show an unexpected twisted shape at its base, and features perpendicular to the jet, which could represent the poles of the accretion disc from where jets are ejected. Through comparing the images of 3C 279 over subsequent days, the astronomers see the finest details changing, opening up the possibility that we are actually seeing both the rotation of the accretion disc (with the shredding and infall of material), and the jet ejection, that has previously only been modeled in computer simulations of these objects.

Jae-Young Kim, leader of the analysis, is enthusiastic and at the same time puzzled: “We knew that every time you open a new window to the Universe you can find something new. Here, where we expected to find the region where the jet forms by going to the sharpest image possible, we find a kind of perpendicular structure. This is like finding a very different shape by opening the smallest Matryoshka doll.” Furthermore, the fact that the images change so fast has also surprised astronomers. “These jets show apparent motions faster than the speed of light (called superluminal motion), as an optical illusion, but this, perpendicular to the expectation, is new and requires careful analysis”, adds Jae-Young-Kim.

The interpretation of these observations is challenging. In particular, observing apparent motions of about 20 times the speed of light in the jet are difficult to reconcile with the early understanding of the source. These results paint a complex picture, where disturbances in the flow of material, known as shocks, are travelling down a bent (and possibly rotating) jet, and producing incredibly high energy gamma-rays.

“To announce this incredible result exactly a year after we brought Pōwehi to the world makes it so special,” offers Jessica Dempsey, Deputy Director of the James Clerk Maxwell Telescope – one of the two Hawaii-based observatories that are part of the EHT. “For our staff here in Hawaii, it is a reminder of the ground-breaking work they continue to contribute to – even if we aren’t up at the summit right now. Like Pōwehi before it, this beautiful image of 3C 279 gives me hope, for us and for our future.”

Fig. 2: The James Clerk Maxwell Telescope (JCMT) located on the slopes of Maunakea, Hawai`i is pictured in the foreground. The JCMT is operated by the East Asian Observatory. Credit: Will Montgomerie

Anton Zensus, Director at the MPIfR and Chair of the EHT Collaboration Board, stresses the achievement as a global effort: “Last year we could present the first image of the shadow of a black hole. Now we see unexpected changes in the shape of the jet in 3C 279, and we are not done yet. We are working on the analysis of data from the centre of our Galaxy in Sgr A*, and on other active galaxies such as Centaurus A, OJ 287, and NGC 1052. As we told last year: this is just the beginning.”

The March/April 2020 observing campaign of the EHT was cancelled due to the CoViD-19 global outbreak. The EHT Collaboration is now determined on the next steps to follow both in new observations and in the analysis of existing data. Geoff Bower, EHT Project Scientist based at the SMA facility in Hilo concludes: ​“This is a small piece of good news during this challenging time. We’re very happy to share with the world results from telescopes on Maunakea and around the globe the insights that we have made into black holes, the most exotic objects in the Universe. Both the SMA and the JCMT produced essential data to make these spectacular images, just as they did for Pōwehi. Stay tuned for new discoveries in the year still to come!”

Here in Hawaii, the state’s effort to “flatten the curve” in the fight against CoViD-19 means that many families now have children – keiki – distance learning at home. Together the Maunakea Observatories are supporting our community by providing online STEM resources for schools, teachers and families. The MKO@Home initiative was launched on March 23rd providing educational videos each Monday, Wednesday and Friday. Topics covered include careers, the solar system, recent discoveries, arts and crafts and more. This week MKO@Home will offer a range of activities and lessons involving Black Holes with a culminating event on April 10th, the State of Hawaiʻi’s Pōwehi Day. Four astronomy professionals will host a live panel discussion at 1:00pm HST answering viewers’ questions on all things astronomy and Black Hole related.

 

Further Information (Links):

Event Horizon Telescope
http://www.eventhorizontelescope.org/

First Image of a black hole, Poōwehi, obtained by the EHT (April 2019)
https://www.eaobservatory.org/jcmt/2019/04/powehi/

James Clerk Maxwell Telescope
https://www.eaobservatory.org/jcmt/

Pōwehi Day proclamation
Governor Ige declares April 10th – Pōwehi Day

MKO@Home on YouTube
http://bit.ly/mkoathome

 

Background Information:

The international collaboration announced the first-ever image of a black hole, Pōwehi, by creating a virtual Earth-sized telescope at the heart of the radio galaxy Messier 87 on April 10, 2019. Supported by considerable international investment, the EHT links existing telescopes using novel systems — creating a new instrument with the highest angular resolving power that has yet been achieved.

The individual telescopes involved in the EHT collaboration are at present: the James Clerk Maxwell Telescope (JCMT), the Submillimeter Array (SMA), ALMA, APEX, the IRAM 30-meter Telescope, the IRAM NOEMA Observatory (expected 2021), the Kitt Peak Telescope (expected 2021), , the Large Millimeter Telescope (LMT),, the Submillimeter Telescope (SMT), the South Pole Telescope (SPT), and the Greenland Telescope (GLT, since 2018).

The telescopes work together through a VLBI technique. This synchronises facilities around the world and exploits the rotation of our planet to form one huge, Earth-size telescope. VLBI allows the EHT to achieve a resolution of 20 micro-arcseconds — equivalent to identifying an orange on Earth as seen by an astronaut from the Moon. The data analysis to transform raw data to an image required specific computers (or correlators), hosted by the MPIfR in Bonn and the MIT Haystack Observatory.

The EHT consortium consists of 13 stakeholder institutes; the Academia Sinica Institute of Astronomy and Astrophysics, the University of Arizona, the University of Chicago, the East Asian Observatory, Goethe-Universität Frankfurt, Institut de Radioastronomie Millimétrique, Large Millimeter Telescope, Max-Planck-Institut für Radioastronomie, MIT Haystack Observatory, National Astronomical Observatory of Japan, Perimeter Institute for Theoretical Physics, Radboud University and the Smithsonian Astrophysical Observatory.

 

Original Paper:

J.Y. Kim, T.P. Krichbaum, A.E. Broderick, et al.: Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution, in: Astronomy & Astrophysics, April 2020
https://doi.org/10.1051/0004-6361/202037493

 

Contact:

Dr. Jessica Dempsey
James Clerk Maxwell Telescope, East Asian Observatory
Email: j.dempsey@eaobservatory.org

Dr. Jae-Young Kim
Max-Planck-Institut für Radioastronomie, Bonn.
Fon: +49 228 525-431
E-mail: jykim@mpifr-bonn.mpg.de

JCMT Semester 20B proposal submission deadline extension

Due to the significant logistical impact of the current COVID-19 pandemic on many members of the JCMT user community, the exceptional decision has been made that the semester 20B PI proposal submission deadline will be extended by two weeks, until 2020-03-31 01:00 (UTC).

Any PIs that have already submitted projects remain free to edit and resubmit them further, and new submissions will be accepted during this two-week period without penalty.

For full details on the 20B Call for proposals, and for proposal submission, please see

https://proposals.eaobservatory.org/

For any questions or concerns regarding any of the above, please feel free to contact us at helpdesk@eaobservatory.org.

JCMT Astronomer helps shed new light on black hole ejections

Dr. Alexandra Tetarenko

Maunakea astronomer, Dr. Alexandra Tetarenko, who works at the James Clerk Maxwell Telescope, has been collaborating with a research group led by Oxford’s Department of Physics which has observed a black hole ejecting material at close to the speed of light, out to some of the largest separations ever seen. These observations have allowed a deeper understanding into how black holes interact with their environment.

Dr. Tetarenko’s research uses a number of telescopes around the world, including the facilities here on Maunakea, to study transient astrophysical systems – objects that change brightness on short timescales. “The system we studied in this instance contains a dynamically confirmed black hole within our Galaxy and another star (not too dissimilar from our sun) orbiting one another. The black hole, due to its strong gravitational pull, syphons material from its companion star in a process known as accretion” says Dr. Tetarenko.

Lead author, Joe Bright, a PhD student at Oxford University’s Department of Physics explains: “Most importantly to this work is the fact that the material is not all lost into the black hole. Outflows are launched away from the black hole at extreme velocities – almost the speed of light – and can be observed with radio telescopes.

“Our research group, consisting of many international astronomers, led an extensive observing campaign on this particular system, known as MAXI J1820+070, after it went into a bright outburst in the summer of 2018. This in itself was remarkable as this type of transient astrophysical system mostly accretes a very small amount of material and so can’t be seen; they do however occasionally go into outburst and only then are they observable.”

A series of images of the black hole MAXI J1820+070 throughout its 2018 outburst, taken with several different radio telescopes. The solid white line marks the position of the black hole, and the dotted lines show the movement of two ejections of plasma launched during the outburst.

The observing campaign of MAXI J1820+070 used the Very Long Baseline Array (VLBA), which has an antenna located in Hawaii on the slopes of Maunakea, along with other telescopes in the UK, USA, and the newly operational MeerKAT telescope in South Africa. “With these facilities we were able to track the connection between accretion and outflows. More excitingly, we were able to observe the system launching ejections of material, and to track these ejections over a wide range of separations from the black hole” explains Dr. Tetarenko.

The group successfully continuously tracked these ejections to extreme distances from the black hole with a range of radio telescopes and the final angular separation is among the largest seen from such systems. The ejections are moving so fast that they appear to be moving faster than the speed of light – they are not, rather this is a phenomenon known as apparent superluminal motion.

Co-lead on the project, Dr. Rob Fender said “We’ve been studying these kinds of jets for over 20 years and never have we tracked them so beautifully over such a large distance. To see them so early on in the operation of a new facility like MeerKAT is fantastic, and – as is often the case – teaches us not to confidently predict what we’re going to see in the future”.

Using the series of radio observations in this study, the authors were able to better estimate how much energy is contained in these ejections using a novel method for this type of system. “Galactic black holes, such as MAXI J1820+070, are thought to be miniature versions of the supermassive black holes that are found at the centre of galaxies. The feedback from these supermassive black holes is thought to be a vital component regulating the growth of galaxies – but these systems evolve on timescales much longer than a human lifetime. Their galactic counterparts, however, evolve quickly and are therefore the perfect systems to study the feedback process and its connection to accretion” explains lead author Joe Bright.

This work is published in the journal Nature Astronomy: https://www.nature.com/articles/s41550-020-1023-5

-20200302

Call for Proposals 20B

The East Asian Observatory is happy to invite PI observing proposals for semester 20B at the JCMT. Proposal submission is via the JCMT proposal handling system, Hedwig. For full details, and for proposal submission, please see

https://proposals.eaobservatory.org/

The 20B Call for Proposals closes on the 16th of March, 2020.

If this is your first time using Hedwig, you should ‘Log in’ and generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.

Please contact us at helpdesk@eaobservatory.org if you have remaining questions.


20A Large Program Open Enrollment

JCMT users are also reminded that the time-limited Open Enrollment period for approved 20A Large Programs has begun. Further details are available here.

– 20200214

Special Supplementary Call for South Korea-led Proposals — 20X (in parallel with 20A)

The proposal submission deadline for this Special 20X Supplementary Call for Proposals is February 28th, 2020.

This Call is using the “Rapid Turnaround”-style peer-review format, in which all proposals submitted for this Call shall be peer-reviewed by the proposal creator (or designated co-author) of other proposals also submitted for this Call.

The proposal peer-review deadline for this Call is March 7th, 2020.

If this is your first time using Hedwig, you should ‘Log in’ and generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.

Please contact us at helpdesk@eaobservatory.org if you have remaining questions.

– 20200205

First Light with new JCMT receiver `Ū`ū

Congratulations to both ASIAA and JCMT staff! We achieved first light with our receiver `Ū`ū on Friday, October 4th, 2019. `Ū`ū is part of the Nāmakanui instrument and works at wavelengths around 1.2mm. Our first observation was taken of CRL2688, a bright sub-mm source between a red giant and planetary nebulae.

Nāmakanui has been offered to JCMT users for single dish observing, initially at 230GHz and later at 345GHz.`Ū`ū is a dual polarization 2-sideband receiver with up to 8GHz of bandwidth (less when using ACSIS). `Ū`ū will be much faster than Rx3Am (which was retired in June 2018) for similar observations. The JCMT Heterodyne Integration Time Calculator https://proposals.eaobservatory.org/jcmt/calculator/heterodyne/ has been updated for `Ū`ū observing.

 

-20191005

JCMT Rapid Turnaround Proposal Submissions Now Invited

JCMT Rapid Turnaround Proposal Submission Call Opens on October 1st, 2019

The East Asian Observatory is pleased to invite proposals requesting Rapid Turnaround (RT) time at the JCMT. All prospective PIs should review the JCMT eligibility requirements page prior to the preparation and submission of a proposal.

A new RT submission cycle shall begin at the start of every month and close at the start of the next month. Any proposals not yet submitted by this time will be treated as still in preparation, and can be submitted during a subsequent cycle for the same semester. RT requests are limited to a maximum of 8 hours for Band 1 – 4 time requests, but are unlimited for Band 5 time requests. The Observatory shall aim to complete successful RT proposals within six months of their formal approval, after which time they shall be removed from the observing queue (regardless of their level of completion).

All RT proposals submitted shall be peer-reviewed by the proposal creator (or designated co-author) of other proposals submitted during the same submission cycle. The proposal peer review deadlines shall normally be two weeks after the close of the regular end-of-month RT proposal submission deadlines.

By submitting an RT proposal, all proposing teams are committing themselves to providing ratings and brief written assessments of several other proposals submitted for this Call by the corresponding deadline. Any proposing team that fails to provide a full set of reviews for their assigned proposals by the corresponding review deadline shall have their own proposal removed from the review process.

The MSBs for all approved RT projects should be created as soon as possible after their corresponding monthly RT review period has completed, ideally before the end of the month following the proposal submission deadline.

For further details regarding RT proposals, please see the relevant Call for Proposals page here. Any further questions should be directed to helpdesk@eaobservatory.org.

New Hedwig users should select ‘Log in’ and create an account. A ‘Help’ facility is available in the upper right corner, and individual Help tags at many other places.

Event Horizon Telescope Collaboration Wins 2020 Breakthrough Prize in Fundamental Physics

On Thursday, September 5th, 2019, the Event Horizon Telescope Collaboration was announced the winner of the prestigious Breakthrough Prize in Fundamental Physics. The $3 million prize, also known as the “Oscars of Science”, will be shared equally with 347 scientists co-authoring any of the six papers published by EHT. JCMT staff feel truly honored to have contributed to the Event Horizon Telescope Consortium that captured the first ever image of the Black Hole, Pōwehi, and look forward to our next EHT observing run in Spring of 2020. Deputy Director of JCMT, Jessica Dempsey, will be donating her portion of the award to the A Hua He Inoa program committed to propelling Hawaiian language and traditions to the global astronomical stage.

 

Event Horizon Telescope Collaboration: Winner of the 2020 Breakthrough Prize in Fundamental Physics

We’re pleased to announce that this year's Breakthrough Prize in Fundamental Physics goes to the Event Horizon Telescope Collaboration. The prize recognizes the team's extraordinary achievement in producing the first photograph of the “shadow" of a black hole. The experiment involved hundreds of collaborators across 8 telescopes, 60 institutions and 20 countries. Tune in to the Breakthrough Prize ceremony on the National Geographic channel November 3. More at https://breakthroughprize.org/News/54.

Posted by Breakthrough on Thursday, September 5, 2019

 

-20190909

Call for Proposals 20A: PI and Large Programs

JCMT Call for Semester 20A PI Programs

The East Asian Observatory is happy to invite PI observing proposals for semester 20A at the JCMT. Proposal submission is via the JCMT proposal handling system, Hedwig. For full details, and for proposal submission, please see

https://proposals.eaobservatory.org/

The 20A Call for PI Proposals closes on the 16th of September, 2019. The Hedwig system permits the submission (and repeated re-submission) of proposals until this deadline.

If this is your first time using Hedwig, you should ‘Log in’ and generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places. Note that from this semester onward, Hedwig also allows a user to create copies of their preexisting proposals, in order to simplify the process of proposal re-submission.

JCMT Call for Large Programs (III)

The East Asian Observatory is also happy to invite applications for the third Call for JCMT Large Programs. At this time, 4,800 hours will be available for Large Programs up until the end of the 22B semester. Submissions will be accepted until the September 16th deadline. Please see here for more details. The proposal handling system, Hedwig, is available here.

For further details regarding current or previous Calls for Proposals, please see the proposal web pages.

Please contact us at helpdesk@eaobservatory.org if you have remaining questions about either of the above Calls for Proposals.

– 20190815

JCMT resumes night time operations

Dear JCMT Community,

We are pleased to announce that we have resumed night time operations at the JCMT. Our first night on sky way Sunday August 11th where we did a functional check out of our systems, took some engineering observations, followed by observations for the Large Program Queue. Our beloved Jim Hoge was the telescope operator in charge and was very happy to be back collecting precious scientific data. Currently we are limited to SCUBA-2 observing only whilst HARP undergoes engineering work. We hope to have it back on sky in September.

We would like to say a big thank you to our JCMT community for their support, patience and understanding. As always the safety of everyone on the mountain is of paramount importance to us.

 

Nāmakanui Has Arrived in Hilo!

Nāmakanui (pronounced “Naaah-mah-kah-noo-ee”), our newest addition to the JCMT instrumentation suite, arrived in Hilo last week and is now out of the box and being tested in Hilo by staff. The Hawaiian name “Nāmakanui” means “Big-Eyes” and it refers to a type of fish found in and around the islands.

When it is fully commissioned, Nāmakanui will be able to look at the sky using one of three receivers. Each receiver carries the name of a different type of Nāmakanui fish: `Ala`ihi (pronounced “ah-la-ee-hee”; 86 GHz), `U`u (pronounced “oo-oo”; 230 GHz), and `Āweoweo (pronounced “aaah-vay-oh-vay-oh”; 345 GHz). `U`u is the first receiver that will be commissioned.

This instrument will be critical for helping take the next Pōwehi image (the Hawaiian name for the Black Hole image at the centre of M87), hooking into the Event Horizon Telescope network. Additionally, it will be capable of delivering a wide range of fantastic science from studying the earliest stages of star formation and the late stages of stellar mass loss to investigating the gas dynamics of galaxies.  It takes 12 hours to cool down Nāmakanui to its operational temperature (4K) and so far the testing is going very well!

This instrument was built by a team at ASIAA (Taiwan) and is on loan the to the JCMT as a spare for the Greenland Telescope. We are very grateful for the opportunity to collect exciting data with this next-generation instrument!
To learn more about this instrument click here: https://buff.ly/2Zkv1lW

 

Special Supplementary Call for South Korea-led Proposals – 19B

The East Asian Observatory invites JCMT observing proposals with Principal Investigators (PIs) affiliated with a South Korean institution only for a special 19B Supplementary Call for Proposals. Proposal submission is via the JCMT proposal handling system, Hedwig. For full details, and for proposal submission, please see here.

The proposal submission deadline for this Special 19B Supplementary Call for Proposals is July 8th, 2019.

This Call is using a new “Rapid Turnaround”-style peer-review format, in which all proposals submitted for this Call shall be peer-reviewed by the proposal creator (or designated co-author) of other proposals also submitted for this Call.

The proposal peer-review deadline for this Call is July 22nd, 2019.

If this is your first time using Hedwig, you should ‘Log in’ and generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.

Please contact us at helpdesk@eaobservatory.org if you have remaining questions.

– 20190215

Spinning Black Hole Sprays Light-speed Plasma Clouds into Space

An international team of astronomers, including Dr Alex Tetarenko, a researcher working at the East Asian Observatory in Hilo, Hawai’i, have discovered rapidly swinging jets coming from a black hole within our own Galaxy the Milky Way, almost 8,000 light-years from Earth. This black hole is much closer to us than Pōwehi, a black hole recently imaged with the Event Horizon Telescope, located around 56 million light-years away from Earth in another Galaxy.

Published today in the journal Nature, the research shows jets from V404 Cygni’s black hole behaving in a way never seen before on such short timescales.

The rapidly spinning black hole in V404 Cygni was observed to eject high-speed clouds of plasma, known as jets, travelling at close to the speed of light. These jets appeared to also be rapidly rotating, with multiple clouds of material ejected just minutes apart.

Lead author Associate Professor James Miller-Jones, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), said black holes are some of the most extreme objects in the Universe.

“This is one of the most extraordinary black hole systems I’ve ever come across,” Associate Professor Miller-Jones said. “Like many black holes, it’s feeding on a nearby star, pulling gas away from the star and forming a disk of material that encircles the black hole and spirals towards it under gravity”.

An artist’s impression of the binary system that includes the black hole V404 Cygni and a sun-like star that orbit one another. Credit: ICRAR.

“What’s different in V404 Cygni is that we think the disk of material and the black hole are misaligned. This appears to be causing the inner part of the disk to wobble like a spinning top and fire jets out in different directions as it changes orientation.”

V404 Cygni, located in the constellation of Cygnus, was first identified as a black hole in 1989 when it released a big outburst of jets and material.

Astronomers looking at archival photographic plates then found previous outbursts in observations from 1938 and 1956.

Associate Professor Miller-Jones said that when V404 Cygni experienced another very bright outburst in 2015, lasting for two weeks, telescopes around the world tuned in to study what was going on.

“Everybody jumped on the outburst with whatever telescopes they could throw at it. So we have this amazing observational coverage” he said.

When Associate Professor Miller-Jones and his team studied the black hole, they saw its jets behaving in a way never seen before.

Where jets are usually thought to shoot straight out from the poles of black holes, these jets were shooting out in different directions at different times.

And they were changing direction very quickly—over no more than a couple of hours.

An artist’s impression of the inner parts of the accretion disk around the black hole V404 Cygni. Credit: ICRAR.

Associate Professor Miller-Jones said the change in the movement of the jets was because of the accretion disk—the rotating disk of matter around a black hole.

He said V404 Cygni’s accretion disk is 10 million kilometres wide, 7 times the diameter of the Sun, and the inner few thousand kilometres was puffed up and wobbling during the bright outburst.

“The inner part of the accretion disk was precessing and effectively pulling the jets around with it. You can think of it like the wobble of a spinning top as it slows down—only in this case, the wobble is caused by Einstein’s theory of general relativity.” Associate Professor Miller-Jones said.

The research used observations from the Very Long Baseline Array, a continent-sized radio telescope made up of 10 dishes across the United States, from the Virgin Islands in the Caribbean to Maunakea, Hawai’i.

Co-author Alex Tetarenko—an East Asian Observatory Fellow working in Hilo Hawai`i, and a recent PhD graduate from the University of Alberta —said the speed the jets were changing direction meant the scientists had to use a very different approach to most radio observations.

Dr Alex Tetarenko outside of the James Clerk Maxwell Telescope Office in Hilo, Hawaiʻi. Credit: Alyssa Clark

“Typically, radio telescopes produce a single image from several hours of observation. But these jets were changing so fast that in a four-hour image we just saw a blur. It was like trying to take a picture of a waterfall with a one-second long exposure” Dr. Tetarenko said.

Observations taken by Dr. Tetarenko and her team with two more telescopes on Maunakea, Hawai`i, the James Clerk Maxwell Telescope (JCMT) and the Sub-millimeter Array (SMA), also hinted at a rapidly evolving jet. Previously published in the journal Monthly Notices of the Royal Astronomical Society, these observations tracking the brightness of the jet over time, revealed extreme flaring events that coincided with the directly imaged jet ejection events.

“The incredible changes in brightness we saw in this JCMT and SMA data, and the model we designed to explain these changes, provided key information needed to develop our imaging method for this paper” she said.

To directly image these rapidly changing jets, the researchers produced 103 individual images, each about 70 seconds long. Miller-Jones and Tetarenko then led the efforts to combine those images into a continuous video—a difficult task, as each image required its own careful analysis.

“The result has been well worth the effort, illustrating this unique and unusual black hole behaviour” Dr. Tetarenko said.

“We were gobsmacked by what we saw in this system—it was completely unexpected,” said study co-author Gregory Sivakoff, a University of Alberta astrophysicist.  “Finding this astronomical first has deepened our understanding of how matter behaves near black holes”.

Study co-author Dr Gemma Anderson, who is also based at ICRAR’s Curtin University node, said the wobble of the inner accretion disk could happen in other extreme events in the Universe too.

“Anytime you get a misalignment between the spin of black hole and the material falling in, you would expect to see this when a black hole starts feeding very rapidly,” Dr Anderson said.

“That could include a whole bunch of other bright, explosive events in the Universe, such as supermassive black holes feeding very quickly or tidal disruption events, when a black hole shreds a star.”

Narrated V404 Cygni Black Hole Animation from ICRAR on Vimeo.

An animation of the precessing jets and accretion flow in V404 Cygni narrated by Associate Professor James Miller-Jones of Curtin University and ICRAR. Zooming in from the high-speed plasma clouds observed with our radio telescope, we see the binary system itself. Mass from the star spirals in towards the black hole via an accretion disk, whose inner regions are puffed up by intense radiation. The spinning black hole pulls spacetime (the green gridlines) around with it, causing the inner disk to precess like a spinning top, redirecting the jets as it does so. Credit: ICRAR.

V404 Cygni Black Hole Jets Simulation from ICRAR on Vimeo.

High-speed plasma clouds ejected from V404 Cygni over a four-hour period on 22nd June, 2015. This movie is made directly from our high-resolution radio images taken with the National Science Foundationʻs Very Long Baseline Array. It shows clouds of plasma in the precessing jets moving away from the black hole in different directions. The scale of the images is approximately the size of our Solar System, and time is shown by the clock in the bottom right-hand corner. Credit: ICRAR and the University of Alberta.

Media Contacts:

  • James Clerk Maxwell Telescope
    • Alex Tetarenko
    • 1-808-969-6519
    • a.tetarenko at eaobservatory.org
  • James Clerk Maxwell Telescope
    • Jessica Dempsey
    • 1-808-969-6512
    • j.dempsey at eaobservatory.org

 

About East Asian Observatory/James Clerk Maxwell Telescope

The EAO (East Asian Observatory) is formed  by EACOA (East Asian Core Observatories Association) for the purpose of pursuing joint projects in astronomy within the East Asian region. The EAO is chartered as a non-profit Hawai`i corporation. Its first task is to assume the operation of the James Clerk Maxwell Submillimetre Telescope (JCMT) on the summit of Maunakea, Hawai`i. Pursuant to an agreement with the University of Hawai`i, the EAO also provides engineering and IT support to the UKIRT Observatory (UKIRT). The JCMT is run by the non-profit organization the East Asian Observatory.

JCMT Plays Critical Role in Producing World’s First Image of a Black Hole – Pōwehi

MAUNAKEA, HAWAIʻI –– Two of the world’s most powerful telescopes, located atop Maunakea, played a vital role in producing the world’s very first image of a black hole. Hawai‘i-based James Clerk Maxwell Telescope (JCMT) and Submillimeter Array (SMA) are part of the unprecedented Event Horizon Telescope (EHT) project. JCMT is operated by the East Asian Observatory; SMA is operated by the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics.

In April 2017, a groundbreaking observational campaign brought together eight telescopes at six locations around the globe to capture an image of Pōwehi, a supermassive black hole at the center of the Messier 87 galaxy.

Pōwehi

Using the Event Horizon Telescope, scientists obtained an image of the black hole at the center of galaxy M87, outlined by emission from hot gas swirling around it under the influence of strong gravity near its event horizon.

“Maunakea makes this discovery and the spectacular image of Pōwehi possible,” said Dr. Jessica Dempsey, deputy director of East Asian Observatory’s James Clerk Maxwell Telescope. “It’s perfect remote position, and the dry conditions on Maunakea’s summit, allow JCMT and SMA to collect the tiny amount of light that only touches our planet in a few very special places. Like the mountain itself, every drop of light we gather is precious.”

Astronomers collaborated with renowned Hawaiian language and cultural practitioner Dr. Larry Kimura for the Hawaiian naming of the black hole. Pōwehi, meaning embellished dark source of unending creation, is a name sourced from the Kumulipo, the primordial chant describing the creation of the Hawaiian universe. Pō, profound dark source of unending creation, is a concept emphasized and repeated in the Kumulipo, while wehi, or wehiwehi, honored with embellishments, is one of many descriptions of pō in the chant.

“It is awesome that we, as Hawaiians today, are able to connect to an identity from long ago, as chanted in the 2,102 lines of the Kumulipo, and bring forward this precious inheritance for our lives today,” said Dr. Kimura, associate professor at University of Hawai‘i at Hilo Ka Haka ‘Ula o Ke‘elikolani College of Hawaiian Language. “To have the privilege of giving a Hawaiian name to the very first scientific confirmation of a black hole is very meaningful to me and my Hawaiian lineage that comes from pō, and I hope we are able to continue naming future blackholes from Hawai‘i astronomy according to the Kumulipo.”

Dr Jessica Dempsey, Dr Larry Kimura, Dr Geoff Bower discuss the results at the JCMT, in front of the 15m dish.

The SMA and JCMT telescopes are key members of the Event Horizon Telescope project, which links together strategically placed radio telescopes across the globe to form a larger, Earth-sized telescope powerful enough to see a Lehua flower petal on the moon.

“SMA and JCMT, working together as one ‘ohana, pioneered the revolutionary technique to see such tiny and faint objects and they were critical in capturing the image of Pōwehi,” said Geoff Bower, chief scientist for Hawai‘i operations of Academia Sinica Institute of Astronomy and Astrophysics. “The spirit of aloha required to unite scientists and observatories across the world was born right here on Maunakea. And powerful new capabilities coming soon at SMA and JCMT mean that Hawai‘i’s groundbreaking contributions to understanding our universe are just beginning.”

The participation of the SMA and JCMT as the far-west anchor point of EHT’s telescope array allowed astronomers to effectively observe and “photograph” supermassive black holes, among the most mysterious and powerful objects in the cosmos.

About James Clerk Maxwell Telescope
Operated by the East Asian Observatory, the James Clerk Maxwell Telescope (JCMT) is the largest astronomical telescope in the world designed specifically to operate in the submillimeter wavelength region of the spectrum. The JCMT has a diameter of 15 meters and is used to study our Solar System, interstellar and circumstellar dust and gas, and distant galaxies. It is situated near the summit of Maunakea, Hawai‘i, at an altitude of 4,092 meters.

The JCMT is operated by the East Asian Observatory on behalf of The National Astronomical Observatory of Japan; Academia Sinica Institute of Astronomy and Astrophysics, Taiwan; the Korea Astronomy and Space Science Institute; Center for Astronomical Mega-Science, China. Additional funding support is provided by the Science and Technology Facilities Council of the United Kingdom and participating universities in the United Kingdom and Canada. The East Asian Observatory also proudly partners with Vietnam, Thailand, Malaysia, Indonesia, and India. Click here for more information.

About Event Horizon Telescope

The EHT collaboration involves more than 200 researchers from Africa, Asia, Europe, North and South America. The international collaboration is working to capture the first-ever image of a black hole by creating a virtual Earth-sized telescope. Supported by considerable international investment, the EHT links existing telescopes using novel systems — creating a fundamentally new instrument with the highest angular resolving power that has yet been achieved.

The individual telescopes involved are; ALMA, APEX, the IRAM 30-meter Telescope, the IRAM NOEMA Observatory, the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope Alfonso Serrano (LMT), the Submillimeter Array (SMA), the Submillimeter Telescope (SMT), the South Pole Telescope (SPT), the Kitt Peak Telescope, and the Greenland Telescope (GLT).

The EHT collaboration consists of 13 stakeholder institutes; the Academia Sinica Institute of Astronomy and Astrophysics, the University of Arizona, the University of Chicago, the East Asian Observatory, Goethe-Universitaet Frankfurt, Institut de Radioastronomie Millimétrique, Large Millimeter Telescope, Max Planck Institute for Radio Astronomy, MIT Haystack Observatory, National Astronomical Observatory of Japan, Perimeter Institute for Theoretical Physics, Radboud University and the Smithsonian Astrophysical Observatory.

This research was presented in a series of six papers published today in a special issue of The Astrophysical Journal Letters.

More information on the Event Horizon Telescope can be found on the EHT website. For a copy of the Press release in `ōlelo Hawai’i click here.

MEDIA CONTACT:

Dylan Beesley, Director, Bennet Group Strategic Communications

dylan at bennetgroup.com

Dr Jessica Dempsey, Deputy Director

j.dempsey at eaobservatory.org

 

Reactions to the news

Selection of Media

Regional Press Releases (in local language)

Additional resources including animations

NSF Media Materials

 

 

Call for Proposals 19B

The East Asian Observatory is happy to invite PI observing proposals for semester 19B at the JCMT. Proposal submission is via the JCMT proposal handling system, Hedwig. For full details, and for proposal submission, please see

https://proposals.eaobservatory.org/

The 19B Call for Proposals closes on the 15th of March, 2019.

If this is your first time using Hedwig, you should ‘Log in’ and generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.

Please contact us at helpdesk@eaobservatory.org if you have remaining questions.

– 20190215

JCMT Transient Survey Team Observes Record-Breaking Flare

On November 26th, 2016, the JCMT Transient Survey Team observed what is estimated to be the most luminous known flare associated with a young stellar object. It is also the first coronal flare discovered at submillimetre wavelengths. The brief flash of light occurred in the direction of a binary system of forming stars known as “JW 566” in the Orion Nebula and it carried ten billion times the amount of energy of the solar flares observed around the Sun.

Left: The Orion Nebula as seen by SCUBA-2 at 850 microns. Right: Two images of
the field surrounded by the green square taken 6 days apart. Small rectangles/triangles show the
positions of known young stars found by other telescopes. On November 20th, 2016, there was
no signal. On November 26th, 2016, the flare was observed while it was already dimming from
its (unseen) maximum brightness.

The flare was discovered by JCMT support astronomer Dr. Steve Mairs using advanced image analysis techniques that had been developed by the Transient Survey team over the past 2 years. The SCUBA-2 observations lasted approximately 30 minutes over which time  the flare faded to half of the brightness measured at the beginning of the scan, indicating the event was short-lived. The flare is thought to be caused by an intense magnetic field re-connection event that energised charged particles to emit gyrosynchrotron/synchrotron radiation.

Press Release: Sky and Telescope, Hawai’i Tribune Herald, Big Island News

Publication: ArXiv, ApJ

The JCMT Transient Survey Team

The JCMT Transient Survey team is an international collaboration of 80 astronomers led by Dr. Gregory Herczeg of Peking (Kavli Institute for Astronomy and Astrophysics) and Dr. Doug Johnstone (National Research Council of Canada). The team has been monitoring 8 star-forming regions in the Milky Way with a monthly cadence since December, 2015. The survey will continue through January, 2020.

The Brightest Quasar in the Early Universe

Observations obtained by the JCMT helped uncover the Brightest Quasar in the Early Universe!

The light from Quasar J043947.08+163415.7 is gravitationally lensed by a dim Galaxy in the foreground, allowing Fan et al. (2019, APJL: 870, 11) to get a good look at this active galactic nucleus at a redshift of z = 6.51 (A distance of ~12.8 Billion Light years!). As the authors note, “This is the first such object detected at the epoch of reionization, and the brightest quasar yet known at z > 5”.

The JCMT is instrumental in observing distant star-forming galaxies. These galaxies have high concentrations of dust that reprocess the starlight such that it is emitted at infrared wavelengths. The light is then redshifted due to the expansion of the universe into the submillimetre regime. The star formation rate is estimated to be 10,000 times higher than that of our own Galaxy, the Milky Way.

Press Release:

Astronomers uncover the brightest quasar in the early universe

Publication:

The Discovery of a Gravitationally Lensed Quasar at z = 6.51


An artist’s rendering of a distance quasar (Credit: ESO/M. Kornmesserhttp://www.eso.org/public/images/eso1122a/)

A bit of history…

The name “Quasar” is a shortened version of the original designation scientists gave to a mysterious signal we didn’t have a scientific interpretation for: a “quasi-stellar radio source” discovered in 1963 by Maarten Schmidt.

Over decades of intensive studies, astronomers have been able to determine that these mysterious signals were coming from intense bursts of light in the hearts of galaxies far, far away.

Most (maybe all!) galaxies contain a supermassive black hole millions to billions times the mass of our Sun. In some of these galaxies, infalling material gets too close to the black hole and it heats up to millions of degrees, exploding outward in a massive release of energy!

We can detect those signals, which we now affectionately call Quasars, at submillimetre wavelengths with the JCMT.

Congratulations to Dr. Xiaohui Fan and his co-authors !

Discovering the Cosmic Nurseries of Giant Elliptical Galaxies

The birth of giant elliptical galaxies is a violent process, with most stars originating from incredible star-forming episodes and several galaxy mergers within large-scale structures (dubbed protoclusters). This formation process happened in the early epochs, when the Universe was only a few billion years old. Currently, researchers using the James Clerk Maxwell Telescope (JCMT) on Maunakea, Hawaiʻi are trying to locate the progenitors of elliptical galaxies, and thus protoclusters, using several observational techniques.

Astronomers have recently discovered a handful of rare, enormous nebulae that copiously emit in the Hydrogen Lyman-alpha transition, a tracer of intergalactic gas. These emissions cover vast distances, up to 30 times larger than the Milky Way. Most of these Enormous Lyman-Alpha Nebulae (ELANe) host multiple active galactic nuclei and are surrounded by several Lyman-alpha emission galaxies. These ELANe are prime candidates for progenitors of elliptical galaxies and massive protoclusters in the early stages of assembly. While these regions are promising, researchers are now tasked with determining the presence of protoclusters and of heavy star formation associated with each ELAN.

An international team of researchers started using the SCUBA-2 instrument on JCMT to characterize these protoclusters and the associated ELAN. Observing at 450 and 850 microns allows SCUBA-2 to capture the emission from dust powered by violent episodes of star formation, something that is not possible with optical telescopes.

Results from the targeted ELAN MAMMOTH-1 field (Fig. 1) revealed the presence of a violent starburst galaxy and emission from a veiled active galactic nuclei (Fig. 2). These sources likely power the extended Lyman-alpha emission, and could be the progenitor of an elliptical galaxy.

In addition, researchers find four times the number of dust-obscured sources in ELAN
MAMMOTH-1 compared to other standard regions. This likely confirms the presence of a rich structure surrounding ELAN MAMMOTH-1, and hints at the presence of a protocluster, hosting the progenitor of an elliptical galaxy. Figure 3 shows the distribution of Lyman-alpha emitting galaxies compared to the SCUBA-2 detections within the observed field. Hopefully, follow-up observations will confirm the relationship between these newly detected sources and a protocluster surrounding the ELAN. For now, these findings seem to agree with the expected theoretical characterizations of cosmic nurseries of giant elliptical galaxies.

Figure 1: ELAN MAMMOTH-1 at z=2.3. This figure shows the surface brightness map (in units of erg/s/cm2/arcsec2) of the Hydrogen Lyman-alpha emission of the ELAN MAMMOTH-1 using a custom-made narrow-band filter. The map is color-coded following the level of surface brightness (see colorbar on the left). The nebula is clearly extended on intergalactic scales (hundreds of projected kiloparsecs; see yellow scale). The red star indicates the position of the likely powering source of this extended emission (see Figure 2). This figure was adapted from Cai et al. (2017). Image Credit: Arrigoni Battaia F., Cai Z.

Figure 2: Spectral energy distribution for the source powering the ELAN MAMMOTH-1. The data-points are from Large Binocular Camera (Large Binocular Telescope) imaging and the Wide-field InfraRed Camera (United Kingdom Infrared Telescope) (Cai et al. 2017 and Xu et al. in prep.; blue), AllWISE source catalog (Wright et al. 2010; orange), the SCUBA-2 (JCMT) observations (magenta), and the FIRST survey (Becker et al. 1994; green). The SCUBA-2 data are key in constraining the spectral energy distribution of this source, allowing researchers to infer the presence of an obscured active galactic nucleus and of intense star formation of the order of 400 solar masses per year. Indeed, the grey line is the best fit model which includes a hot-dust emission component inherent of active galactic nuclei and a strong dust emission likely powered by intense star formation. This figure was adapted from Arrigoni Battaia et al. (2018) Image Credit: Arrigoni Battaia F./European Southern Observatory.

 

Figure 3: Location of known sources surrounding the ELAN MAMMOTH-1. The small black circles indicate the known galaxies emitting Lyman-alpha emission within the known galaxy large-scale structure surrounding the ELAN MAMMOTH-1. The brown crosses indicate the quasars within such large-scale structure. The large blue circles and yellow squares indicate the sources detected within the two bands of the SCUBA-2 instrument, 850 and 450 microns respectively. The orange diamonds indicate the only two sources with both Lyman-alpha emission and SCUBA-2 detection. One of them is the ELAN MAMMOTH-1. The number of detected sources at 850 microns in the SCUBA-2 data reveals four times more dust-obscured sources than in “standard” regions, likely confirming the presence of a rich protocluster surrounding the ELAN MAMMOTH-1. The brightest of the SCUBA-2 detections coincide with the peak of the known galaxy distribution (traced by the green contours) within this large-scale structure (numbers close to each blue circle indicate the flux at 850 microns). This figure was adapted from Arrigoni Battaia et al. (2018) Image Credit: Arrigoni Battaia F./European Southern Observatory.

Media Contacts:

European Southern Observatory/Max-Planck Institute for Astrophysics
Fabrizio Arrigoni Battaia
farrigon at eso.org

European Southern Observatory
Chian-Chou Chen
ccchen at eso.org

James Clerk Maxwell Telescope
Harriet Parsons
h.parsons at eaobservatory.org

About The Authors

The international authors of this paper are from European Southern Observatory, Germany, Durham University, UK, University of California, USA, Leiden University, Netherlands, Tsinghua University, China, and the Korea Astronomy and Space Science Institute, South Korea.

 

 

Observing Comet 46P/Wirtanen from the JCMT

Comet 46P/Wirtanen is known as a hyperactive comet. Hyperactive comets are a small family of comets whose activity levels are higher than expected. In addition to being hyperactive 46P/Wirtanen will make the 10th closest ever cometary approach to Earth of modern times (0.08au) this month.

JCMT with Comet 46P/Wirtanen. Credit: EAO/JCMT/Kevin Silva

JCMT astronomers will take this opportunity to map the distribution of chemicals like hydrogen cyanide and methanol in this comet’s coma, to try and determine if these chemicals emerged directly from the comet nucleus or were formed in the coma from other chemicals. This mapping will be performed by the JCMT spectral line instrument; HARP. In addition to observing these chemicals the astronomers are hoping the comet will be bright enough to  make other measurements that that will shed light on the original location and conditions of the comet’s formation within the very early stages of what we now know to be our Solar System.

JCMT comet hunters Iain Coulson, Yi-Jehng Kuan, Fang-Chun Liu along with Support Astronomer (Steve Mairs)

For more information on comet 46P/Wirtanen visit: http://wirtanen.astro.umd.edu/46P/

Comet 46P/Wirtanen from the NASA Astronomy Picture of the Day 2018 November 15, Image Credit & Copyright: Alex Cherney (Terrastro, TWAN).

Maunakea Gender Equity and Diversity Survey 2018 Report

In July 2018, the Maunakea Gender Equity and Diversity Committee distributed a survey to the staff at the Maunakea astronomical organizations. The survey was intended to invite opinion on the current state of equity and diversity in the Maunakea astronomy community and seed conversation and ideas for enhancing diversity and inclusion in our organizations across our islands.

The report on the results of the survey is here:

Maunakea Gender Equity and Diversity Survey 2018 Report

and the Appendix A, listing the survey questions, is provided for reference:

Gender Equity and Diversity Survey questions

The first results are presented by Jessica Dempsey at the Maunakea Users’ Meeting on October 4th, 2018. A PDF of the talk is linked here for convenience. For usage or distribution of these data, please contact Jessica Dempsey: j.dempsey “at” eaobservatory.org.

Photo by Oro Whitley

– 20181004

 

Discovering Magnetized Inflow Accreting to the center of Milky Way Galaxy – An important force to transport gas to the supermassive black hole Sagittarius A*

Is magnetic field an important guiding force for gas accreting to supermassive black hole (SMBH) — for example, the one that our Milky Way Galaxy hosts? The role of magnetic field in this subject is little understood and trying to observe it has been challenging to astronomers. Researchers at the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Taiwan, led by Dr. Pei-Ying Hsieh, have utilized a measurement of high resolution data by using the instruments on the James Clerk Maxwell Telescope (JCMT). Their result provides clear evidences in showing that the orientation of the magnetic field is in alignment with the molecular torus and ionized streamers rotating with respect to Sagittarius A* – the black hole our home galaxy hosts. The findings are published in Astrophysical Journal in 2018 August 2nd (2018, ApJ, 862, 150).

Color-composite images of the SMA map tracing the molecular gas of the CND (blue) and the Very Large Array (VLA) 6 cm map tracing the mini-spiral (red). The magnetic field of the JCMT-SCUPOL data and the model are overlaid with the white segments in the upper right and low left panel, respectively. The location of SgrA* is labeled with the black cross. The CND is a molecular torus (ring) rotating with respect to the supermassive black hole SgrA* in our Galaxy. The mini-spiral is hypothesized to be originated from the inner edge of the CND. The alignment of the magnetic field line along with the CND and the mini-spiral tells us that they are linked with a coherent magnetic field. The team found the magnetic field is able to guide the ionized particles from the CND to the mini-spiral, which suggests a picture the footprint of inflow near SgrA*. In the lower right panel, the latest dust polarization data taken in 2017 measured with the new instruments POL-2 installed in JCMT is shown. The magnetic field is shown with the white segments. An improved spatial coverage and sensitivity clearly reveal the connection between the CND and the mini-spiral at even higher spatial sampling than the JCMT-SCUPOL data, which confirm the picture the team proposed.


SgrA* – the best laboratory to study black hole feeding in the sky

Sagittarius A* (SgrA*),  being the closest SMBH in our home in the universe, the Milky Way Galaxy, has been targeted by many scientists to understand the nature of gas accretion in the past decades. Observing the gas accretion onto SMBH is critical to help us to understand how it releases tremendous energy.

The circumnuclear disk (CND) is a molecular torus rotating with respect to SgrA*, within which are the ionized gas streamers called mini-spiral (also called SgrA West) filling the molecular cavity. The mini-spiral is hypothesized to be originated from the inner edge of the CND. The CND, being the closest “food reservoir” of SgrA*, is therefore critical on the understanding of the feeding of SgrA*. However, looking for the physical evidences to connect the CND and the mini-spiral puzzles astronomers since they were discovered a few decades ago.

Intensive measurements of dynamical movements orbiting SgrA* have been done in the past decades, but another important force – the magnetic field – is rarely probed. This is solely because the weak polarized signal generated by the magnetic field from dust emission is difficult to measure. However, the magnetic field is expected to be important for material orbiting within and around the CND as the magnetic stress acting on the rotating disk can exert a torque to extract angular momentum from rotating gas, and thus drive gas inflows. Besides, The magnetic tension force is also possible to draw the gas back from the gravitational pull. Taking advantage of excellent atmospheric conditions of Mauna Kea summit at 4000 m, and large aperture size of the JCMT (15 m in diameter), the submillimeter polarization experiments were successfully obtained toward the Galactic Center to understand the role of magnetic field.

Tracing Magnetized Accreting Inflow

The team utilized the dust polarization data obtained by the JCMT-SCUPOL instrument to image the orientation of the magnetic field. A detailed comparison with higher-resolution interferometric maps from the Submillimeter Array (SMA) reveals that the magnetic field aligns with the CND.  Moreover, the innermost observed magnetic field lines also appear to trace and align with the mini-spiral coherently. This is the first attempt to reveal the footprint of inflow linking the CND and the mini-spiral since they were discovered a few decades ago. The comparison of the model and data reinforces the key idea that the CND and the mini-spiral can be treated as a coherent inflow-system.

The team found that the magnetic field is dynamically significant towards the CND and the mini-spiral. This finding tells us that the magnetic field is able to guide the motion of the ionized particles originated in the CND, and produce the observed spiral pattern of the mini-spiral. Dr. Hsieh said, “We found the magnetic field is critical to explain the inflow structure and will also help to understand the inflow picture in other galaxies hosting black hole similar to SgrA*. “

Paper and research team:

These observation results were published as Hsieh et al. “A Magnetic Field Connecting the Galactic Center Circumnuclear Disk with Streamers and Mini-spiral -Implications from 850 micron Polarization Data” in the Astrophysical Journal (published in the Astrophysical in August 2nd).

This research was conducted by:

Hsieh, Pei-Ying (ASIAA); Koch, Patrick M. (ASIAA); Kim, Woong-Tae (SNU); Ho, Paul T. P. (ASIAA; EAO); Tang, Ya-Wen (ASIAA); Wang, Hsiang-Hsu (CUHK)

This research is supported by the Ministry of Science and Technology (MoST) of Taiwan through the grants MoST 105-2811-M-001-141, MoST 106-2811-M-001-136, MoST 104-2119-M-001-019-MY3, MOST 105-2112-M-001-025-MY3, Academia Sinica Career Development Award, and the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST; No. 3348-20160021).

Related Links:

https://sites.google.com/asiaa.sinica.edu.tw/newsite/ASIAA_TAIWAN_News/20180817

https://www.asiaa.sinica.edu.tw/news/shownews.php?i=0e2af7b8c43775f78802f11ca0063488

-20180816

Call for Proposals 19A

The East Asian Observatory is happy to invite PI observing proposals for semester 19A at the JCMT. Proposal submission is via the JCMT proposal handling system, Hedwig. For full details, and for proposal submission please see

https://proposals.eaobservatory.org/

The 19A Call for Proposals closes on the 15th of September, 2018.

If this is your first time using Hedwig, you should ‘Log in’ and generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.

Please contact us at helpdesk@eaobservatory.org if you have remaining questions.

– 20180815

CHIMPS-2 members meet in Liverpool

Members of the CHIMPS-2 Large Program met for a two day meeting in Liverpool on June 28th and 29th. The meeting covered data collection, reduction and analysis with astronomers from all over the globe. For more information on the CHIMPS-2 project click here. We wish the team “clear skies” as they look to expand the JCMT CO heterodyne data towards the Galactic Centre this summer.

– 20180708

First observations of the magnetic field inside the Pillars of Creation: Results from the BISTRO survey

The BISTRO (B-Fields in Star-Forming Region Observations) Survey has for the first time mapped the magnetic field in the dense gas of the ‘Pillars of Creation’, using instruments on the James Clerk Maxwell Telescope (JCMT). The Pillars of Creation, in the Messier 16 star-forming region, which is also known as the Eagle Nebula, were the subject of one of the most iconic images taken by the Hubble Space Telescope (HST). The Pillars are a set of columns of cold, dense gas protruding into a region of hot, ionized plasma. The Pillars have nurseries of new stars forming at their tips, and are a particularly dramatic example of a feature found in many regions of interstellar space in which high-mass stars are forming.

We present the first high-resolution observations of the Pillars in polarized light at submillimeter wave- lengths – submillimeter light being on the cusp between infrared and radio waves, where the cold, dense dust and gas which will form the next generation of stars emits most of its light. Light emitted from these dusty regions is polarized perpendicular to the direction of its local magnetic field, and so we can use our observations to directly probe the magnetic field morphology within the dense gas of the Pillars of Creation. Our observations were taken at a wavelength of 0.85 mm as part of the BISTRO Survey, using the POL-2 polarimeter on the SCUBA-2 submillimeter camera at the JCMT. They show that the magnetic field runs along the length of the pillars, at a significantly different angle to the field in the surrounding ionized plasma, and has an estimated strength of approximately 170 − 320 microGauss (1.7 − 3.2 × 10−8 Tesla), an intermediate magnetic field strength for a region of space which is forming stars.

An illustrative figure of the BISTRO magnetic field vectors observed in the Pillars of Creation, overlaid on a HST 502 nm, 657 nm and 673 nm composite – HST imaging from Hester et al. (1996, AJ 111, 2349).

Young hot stars, with masses more than eight times that of the Sun, produce large numbers of high-energy photons. These high-energy photons ionize a volume of the region within which they form, splitting hydrogen atoms into pairs of protons and elections. As the shock front between the material ionized by the young stars and the untouched neutral material advances, complex structures form in the dense gas at the interface. Particularly, pillars of dense, neutral gas like those in M16 are found protruding into the ionized region, apparently left behind by the advancing shock front. The formation and evolution of these pillars is not well-understood – debate continues as to whether these pillars form behind obstructions to the shock front, or whether they can form from turbulent instabilities in the shock front itself. The role of the magnetic field in the formation of the Pillars is particularly uncertain, since the strength of the magnetic field in the dense parts of the Pillars has not been measured until now.

BISTRO magnetic field vectors overlaid on a HST 502 nm, 657 nm and 673 nm composite image of Pillar II. The magnetic field runs roughly parallel to the Pillar’s axis. No polarization is detected at the Pillar’s tip – this depolarization is consistent with a horseshoe-shaped magnetic field morphology on scales smaller than the beam.

Our observations of the magnetic field running along the length of the Pillars are consistent with the Pillars being formed by compression of gas with an initially weak magnetic field: the magnetic field has not had the strength to resist being dragged into its current configuration by the motions of the gas. However, the magnetic field strength appears to have been increased by being compressed in the forming pillars. The magnetic field strength that we estimate is large enough to magnetically support the sides of Pillars against collapsing radially under pressure from the surrounding hot plasma, and to prevent the Pillars collapsing under their own gravity. It is important to note though that the Pillars are still being destroyed by the same shock interaction that created them: the magnetic field that we measure is not strong enough to prevent the Pillars being gradually eroded from their tips by the effects of the young stars in the region. Our results suggest that the evolution and lifetime of the Pillars may thus be strongly influenced by the strength and orientation of their magnetic field: the Pillars’ longevity results from magnetic support.

Our proposed evolutionary scenario: (a) an ionization front moving perpendicular to the am- bient magnetic field approaches an existing over-density in the molecular gas. (b) The ionization front is slowed by the over-density. The flux-frozen magnetic field ‘bows’ into the forming pillar. (c) The com- pressed magnetic field supports the pillar against further gas-pressure- and gravity-driven radial collapse, but cannot support against longitudinal erosion of the over-density by ionizing photons. Throughout, dark blue shading represents molecular gas and light blue shading represents ionized material. The ionization front is shown as a black line. Grey dashed lines indicate the local magnetic field direction. Red arrows represent photon flux, black arrows represent magnetic pressure, and green arrows represent thermal gas pressure.

The James Clerk Maxwell Telescope, located on Mauna Kea in Hawaii, is operated by the East Asian Observatory. The BISTRO Survey is a large team of scientists working to understand the role of mag- netic fields in the formation of stars, with members from across the partner regions of the East Asian Observatory: China, Japan, South Korea, Taiwan and Vietnam, and from participating universities in the United Kingdom and Canada.

This research has been accepted for publication by The Astrophysical Journal Letters. A pre-print is available at http://arxiv.org/abs/1805.11554.

Kate Pattle, Derek Ward-Thompson, Tetsuo Hasegawa, Pierre Bastien, Woojin Kwon, Shih-Ping Lai, Keping Qiu, Ray Furuya, David Berry and the JCMT BISTRO Survey Team

Inquiries about this research: Email: kpattle@gapp.nthu.edu.tw

The “Pillars of Creation” is one of the most well-known images in astronomy, and it is very exciting to be able to add to what is known about this part of the sky.  The pillars are beautiful structures – remarkable for their highly coherent structure within the dynamic and highly energetic environment of a region forming high-mass stars.  We have found that the magnetic field within the Pillars is well-ordered, running along the length of the pillars, and is strong enough to influence the future evolution of the pillars, helping to support them against collapse.  This is an intriguing result because it shows us that the magnetic field is important to the region now, but also that it was likely not very important during the period when the pillars were forming.  The field appears to have changed significantly from its original direction to run along the pillars as they were formed by a shock interaction caused by nearby young stars.  This could not have happened if the magnetic field were strong enough to resist being moved.  Our results suggest that the importance of the magnetic field to the Pillars of Creation has evolved over time along with the Pillars themselves.

The JCMT is the only telescope in the world which could have made these observations – the JCMT’s POL-2 polarimeter and SCUBA-2 camera are a unique combination of instruments, observing at the wavelengths at which cold dust in star-forming regions emits most of its light.  POL-2 provides information on the magnetic field on the scale of objects such as the Pillars of Creation which is not available anywhere else.

We have already had a proposal accepted by the Submillimeter Array (SMA) on Mauna Kea to observe the magnetic field in the tips of the pillars in more detail.  In our JCMT observations we see the magnetic field disappear at the tips of the pillars.  This “depolarization” could be caused by tangled magnetic field lines or a complete reversal of magnetic field direction in the pillars’ tips causing the field to cancel out in our observations.  By observing at higher resolution with the SMA we will be able to see what the magnetic field looks like on these small scales, and to better understand what role the magnetic field is playing in the shock interaction which is driving the pillars’ evolution.  We could also potentially look in more detail still at the magnetic field in clumps in the pillars’ tips using the Atacama Millimeter/submillimeter Array (ALMA) in Chile, or observe the pillars in polarized near-infrared light using the airborne SOFIA observatory.

-2018/06/05

Call for Proposals 18B

The East Asian Observatory is happy to invite PI observing proposals for semester 18B at JCMT. Proposal submission is via the JCMT proposal handling system, Hedwig. For full details, and for proposal submission please see

https://proposals.eaobservatory.org/

The 18B Call for Proposals closes on the 15th of March, 2018.

If this is your first time using Hedwig, you should ‘Log in’ and generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.

Please contact us at helpdesk@eaobservatory.org if you have remaining questions.

– 20180214

18-month twinkle in a forming star suggests
 the existence of a very young planet

Discovery made possible by a leap in submillimetre radio astronomy technology,
 comparable to viewing videos instead of photos.

November 1, 2017 — An international team of researchers have found an infrequent variation in the brightness of a forming star. This 18-month recurring twinkle is not only an unexpected phenomenon for scientists, but its repeated behavior suggests the presence of a hidden planet.

This discovery is an early win for the James Clerk Maxwell Telescope (JCMT) Transient Survey, just one-and-a-half years into its three-year mandate to monitor eight galactic stellar nurseries for variations in the brightness of forming stars. This novel study is critical to understanding how stars and planets are assembled. The survey is led by Doug Johnstone, Research Officer at the National Research Council of Canada and Greg Herczeg, Professor at Peking University (China), and is supported by an international team of astronomers from Canada, China, Korea, Japan, Taiwan and the United Kingdom.

“This variation in the brightness or twinkle of the star EC53 suggests that something large is disrupting the gravitational pull of the forming star. The fact that it recurs every 18 months suggests that this influence is orbiting around the star – it’s quite likely a hidden, forming planet,” says Doug Johnstone. It is thought that a companion planet is orbiting the star, and its passing gravitational pull disrupts the rate of the gas falling onto the forming star, providing a variation in the observed brightness, or light curve, of the star.

 

Young stars are born in regions of the galaxy where molecular gas is abundant. When the star is young, gas and dust form a thick cloud that surrounds the star. Some of this material quickly flattens into a disk, in which planets will form. The cloud blocks the star itself from optical view, so astronomers study the star indirectly by using the cloud to learn details about the star growing inside. The star builds up its mass as gravity attracts gas to move from the disk onto the star, a process that also releases significant energy that heats up the surrounding gas cloud. Astronomers use telescopes sensitive to sub-millimetre wavelengths, like the JCMT, to measure the cloud brightness and reveal details about the growth of the star.

EC53’s light curve anomaly was discovered by Hyunju Yoo, graduate student at Chungnam National University and advisor Jeong-Eun Lee, Professor at Kyung Hee University (South Korea), through careful analysis of monthly observations of Serpens Main, a stellar nursery known to contain many forming stars. Although the brightness of EC53 has been observed to vary periodically at near-infrared wavelengths for some time, these sub-millimetre observations were essential in validating that the brightness variation was due to heating from gas accreting onto the forming star, rather than variations in the cloudiness of the environment.

“What caught my eye was a new round of data that showed a sudden brightness that hadn’t existed in previous observations,” says Lee. “I knew that something unique and interesting must be happening around this forming star. It turned out that it is indeed a very special object, providing a new window into how stars and planets form.”

A deeper understanding of the formation of stars and planets

For the remainder of the three-year sub-millimetre survey, the team will continue to monitor EC53 and will also be searching for additional young stars showing variations in growth to learn more about how stars and planets assemble. There are already a half-dozen additional candidate variables within the survey. By studying these stars, and using additional telescope facilities such as the powerful Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, the study will provide new and unique insight into the timescale for the formation of stars and planets, including whether planets form during or after the assembly of the star.

“This discovery marks a turning point; in a sense, it’s like sub-millimetre astronomy is moving from taking pictures of our galaxy to taking videos,” says Greg Herczeg. “The last 25 years have been devoted to perfecting observing techniques and instruments to allow us to see early star formation. But with recent advances in technology, we can now observe regions changing over time, for a deeper understanding of how stars form. This discovery is just one example of how much more we can now learn.”

Monitoring the brightness of forming stars over time using sub-millimetre wavelengths is an unconventional approach to observing that has been made possible by recent advances in imaging technology, like SCUBA-2, and data reduction processing which enables precise calibration and measurement.

The JCMT resides at the summit of Maunakea in Hawaii and is the largest single-dish sub- millimetre telescope in the world. The JCMT is operated by the East Asian Observatory, a partnership between China, Taiwan, South Korea and Japan, with support from the astronomy communities in Canada and the United Kingdom. The university-led contributions from Canada are supplemented by the NRC’s support for the JCMT archive at the Canadian Astronomy Data Centre.

This discovery has been accepted for publication in Astrophysical Journal and is available online.

This story is distributed on behalf of: The National Research Council of Canada, Peking University and Kyung Hee University.

Contacts

Media Relations Team
National Research Council of Canada
1-855-282-1637 (in Canada)
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001-613-991-1431 (International)
media@nrc-cnrc.gc.ca
Twitter: @nrc_cnrc

The Kavli Institute for Astronomy and Astrophysics (KIAA)
Peking University
Shuyan Liu
+86-10-6275-6630
shuyan@pku.edu.cn

Kyung Hee University
Min-Jae Jung
Communications team
+82-10-6626-6694
ddubi17@khu.ac.kr

James Clerk Maxwell Telescope
Steve Mairs
1-808-969-6572
s.mairs@eaobservatory.org

– 20171101

“Stray Black Holes” discovered in the Galactic Centre

A research team led by Japanese astronomers using data taken with the James Clerk Maxwell Telescope (JCMT), have conducted detailed radio spectral observations of molecular gas around the nucleus of our Milky Way Galaxy, Sgr A*.

As a result, the team has discovered two compact molecular clouds that have extremely broad velocity widths at distances of approximately 20 light years from Sgr A*. Despite the fact that these peculiar clouds have large kinetic energies, no energy source has been found there. Thus, the team interprets that each of the clouds is driven by the high-velocity plunge of an isolated (invisible) black hole without a companion star into a giant molecular cloud.  This implies that multiple “stray black holes” are floating around a supermassive black hole lurking at the Galactic center.

Illustration of stray black holes floating around a supermassive black hole at the Galactic center.

1. Important Points

  • The team studied two unusual molecular clouds. These two clouds were discovered in the vicinity of the Galactic nucleus of the Milky Way, Sgr A*.  Their motions and physical properties were studied and their motions were deemed to be abnormal.
  • The origin of each of unusual clouds cannot be explained by an interaction with a supernova. The clouds are also not explained by a bipolar outflow from a protostar. This implies that the origin is likely to be an obscure astrophysical phenomena.
  • As a result of the large kinetic energies observed combined with no a lack of an obvious energy source, the team theorizes that the driving sources may be black holes rapidly plunging into molecular clouds.

2. Research Background

The Galactic nucleus Sgr A* is located at a distance of approximately 26,000 light years from the Earth, and recognized as a supermassive black hole with 4 million solar masses. The origin of the supermassive black hole remains unresolved. In contrast, a stellar mass black hole, which has a mass ranging from about three to several tens of solar masses, is known to be formed by the gravitational collapse of a massive star heavier than 30 solar masses. It is theoretically predicted that several hundred million stellar mass black holes lurk in the Milky Way.

However, the number of black hole candidates currently detected in the Milky Way is only 60. In general, gas and dust drawn by the gravitational force of a black hole constitute an accretion disk around it. After the materials are sufficiently accreted and the accretion disk gets hotter and emits intense electromagnetic waves. Typically stellar mass black holes in the Milky Way have been found by detection of X-ray radiation from their accretion disks. In order for an accretion disk to be continuously shining, a fueling source, i.e. a companion star, must be in the close vicinity of a black hole. However, such black holes (those with close companions) are very rare. Most of back holes are likely to be isolated and inactive. Thus, countless “stray black holes” should be floating in the Milky Way.

3. Research Results

The research team conducted spectral line observations of the Galactic central region within 30 light years of the Galactic nucleus Sgr A* to investigate kinematics and physical properties of molecular gas surrounding the nucleus, using the JCMT. In the observations, the team discovered two unusual molecular clouds (HCN–0.009–0.044 and HCN–0.085–0.094) with diameters of about 3 light years and extremely broad velocity widths wider than 40 km/s (See Figure b below). Each of these unusual clouds appears to stem from a larger cloud. Their motions seem to be different from those of well-known molecular clouds around the nucleus (See Figure a, and c below).

These motions imply enormous kinematic energies (>1047 erg). Such enormous kinetic energy may be produced by an interaction with a supernova explosion or a bipolar outflow form a bright massive protostar. However, no evidence of a supernova or a bright protostar was found toward these peculiar clouds.   The origin is probably “something” other than well-known astrophysical phenomena; inactive stellar mass Black Holes.

The data used to make this discovery (a) Position-velocity diagram along the yellow vertical line in the panel (b). (b) Integral intensity map of the Galactic central region around Sgr A* (shown by a white star) in the hydrogen cyanide (HCN) 354.6 GHz spectral line. The light-blue cross marks indicate the locations of the discovered peculiar compact clouds (HCN–0.009–0.044 and HCN–0.085–0.094). (c) Position-velocity diagram along the yellow horizontal line in the panel (b). (d, e) The spectral lines detected toward the peculiar clouds.

The team proposes that the high kinematic energy results from: “a high-speed compact gravitational source plunging into a molecular cloud and the gas is dragged along by the gravity of the compact source to form a gas stream.”

According this “plunge scenario”, such unusual clouds can be formed in two cases as follows:

  • A massive compact object with a mass larger than about 10 time the mass of our Sun plunges with a high velocity of about 100 km/s into a molecular cloud.
  • A compact object with a mass similar to that of the Sun plunges with a ultra high velocity of about 1000 km/s into a molecular cloud.

In the case 1), the candidate for the plunging object is a massive star or black hole. In the case 2), the candidate is a hypervelocity star which moves so fast that it can escape from the gravity of the Galaxy. However, no hypervelocity star has been found in the Galactic center and the number is theoretically predicted to be much less than that of black holes. Therefore, the driving sources of the two discovered clouds are likely to be massive stars or black holes. In addition, no bright massive stars have been found toward these clouds. Thus, a “stray black hole” floating around the supermassive black hole is the most plausible candidate for each of the driving sources of the two clouds.

4. Research Significance

This work is very meaningful since the possibility that a number of “stray black holes” are floating around a supermassive black hole at the Galactic center was indicated by the observational study for the first time.

The team has already discovered the peculiar molecular cloud in the Galactic disk (Bullet) that may also be driven by a high-velocity plunge of a stray black hole (Yamada et al. 2017, https://www.nao.ac.jp/en/news/science/2017/20170202-aste.html).

These studies which are based on spectral line observations of molecular gas suggest a new method of potentially discovering inactive isolated black holes that are undetected by traditional method such as X-ray observations. The number of black hole candidates is expected to dramatically increase by applying research methods similar to this work.

Recently, by detection of gravitational waves, it has been confirmed that black holes merge and grow. The team has also discovered a candidate for an intermediate mass black hole with a mass of 100 thousand solar masses at a distance of about 200 light years from the Galactic nucleus

(Oka et al. 2017, https://www.nao.ac.jp/en/news/science/2016/20160115-nro.html).

This intermediate mass black hole and stray black holes discovered in this work possibly contribute to growth of the supermassive black hole in future.

Inquiries about the research

Professor Tomoharu Oka
Department of Physics
Keio University Science and Technology
TEL: +81-45-566-1833 FAX: +81-45-566-1833

E-mail: tomo@phys.keio.ac.jp

http://aysheaia.phys.keio.ac.jp/index.html

These observation results were published as Takekawa et al. “Discovery of Two Small High-velocity Compact Clouds in the Central 10 pc of Our Galaxy” in the Astrophysical Journal Letters in July 2017.

The team behind this work are Shunya Takekawa, a Ph.D. student at Keio University, Japan, and Tomoharu Oka, a professor at Keio University.

This study was supported by a Grant-in-Aid for Research Fellow from the Japan Society for the Promotion of Science (15J04405).

Hawaii Island Inquiries about the research

Dr Harriet Parsons
EAO/JCMT
660 North A’Ohoku Place
Hilo, Hawaii, 96720

E-mail: outreach@eaobservatory.org

 – 2017/07/18