Weather

Proposers should also be mindful of the historical fraction of time in each weather Grade in particular noting the wide variation in ours per weather Grade obtained in any one semester.

The Expanding Partner Program

PIs from Malaysia, Vietnam, Indonesia, India, Brazil and Argentina are welcome to apply for a limited amount of time (<5 hours per program this time constraint is not limited in Grade 5 time) under the “Expanding Partner Program” – a program to encourage astronomers from new JCMT partners to make use of the JCMT.

*** Completion of any science program awarded time is not guaranteed. Approval reliant upon the program being technically feasible, without clashing with existing proprietary data. Data collection is dependent on weather/instrument/queue pressures with adjustments in line with recommendations by the TAC. Under the “Expanding Partner Program” priority will be given to new users of the JCMT.

Maunakea Hawaii – JCMT astronomers studying stellar nurseries, the birthplace of stars in our galaxy, have found that nearly  half of stars in the Galaxy are formed in binary/multiple stellar systems (think twins, triplets, quadruplets). Despite the prevalence of binary/multiple births previous studies of stellar nurseries have concentrated more on how single stars form. The origin of binary/multiple stellar systems remains a mystery to astronomers.

The birth of all stars requires the gravitational collapse of cold dense pockets of gas and dust (known as cores) found in what are known as molecular clouds. However, previous investigations have rarely addressed how the properties of the host dense cores affect stellar multiplicity. To address this question a team of astronomers using the JCMT in Hawaii and ALMA telescope in Chile looked to the Orion Cloud complex – of the closest active star formation region. Located in the Orion constellation at about 1,500 light-years away this stellar nursery is an ideal laboratory for testing various models of star formation.

Using the JCMT telescope, astronomers identified 49 cold dense cores in the Orion clouds, locations which are in the process of forming young stars. The team then used the Atacama Large Millimeter/submillimeter Array (ALMA) to unveil the internal structures within these dense cores.

G205.46-14.56 clump located in Orion molecular cloud complex. The yellow contours stand for the dense cores discovered by JCMT, and the zoomed-in pictures shows the 1.3mm continuum emission of ALMA observation. These observations give insight into the formation of various stellar systems in dense cores.

Using the high-resolution ALMA observation, astronomers find that about 30% of the 49 cores are giving birth to binary/multiple stars, while the other cores are only forming single-stars. Astronomers then estimated the physical characteristics (size, density and mass) of these dense cores from the JCMT observations. Surprisingly, astronomers found that cores forming binary/multiple stars tend to show higher densities and higher masses than those cores forming single stars, although the sizes of various cores show no much differences. “This is understandable. Denser cores are much easier to fragment due to the perturbations caused by self-gravity inside molecular cores.” says Qiuyi Luo, a Ph.D. student at Shanghai Astronomical Observatory, who is the first author of this work published in The Astrophysical Journal.

The team also observed the 49 cores in N₂H⁺ J=1-0 molecular line with the Nobeyama 45-m telescope. They found that N₂H⁺ line widths of cores forming binary/multiple stars are statistically larger than that of cores forming single stars. “These Nobeyama observations provide a good measurement of turbulence levels in dense cores. Our findings indicate that binary/multiple stars tend to form in more turbulent cores”, says Prof.Ken’ichi Tatematsu, who lead the Nobeyama observations.

Summarizing the findings Qiuyi Luo said “In a word, we found that binary/multiple stars tend to form in denser and more turbulent molecular cores in this study”. Adding to this comment Sheng-Yuan Liu at ASIAA, co-author of this study stated “The JCMT has proven to be a great tool for uncovering these stellar nurseries for ALMA follow-ups. With ALMA providing unprecedented sensitivity and resolution so that we can do similar studies toward a much sample of larger dense cores for a more thorough understanding of star formation”.

As for future work, corresponding author and lead for the ALMA data Tie Liu, commented: “we have yet to look at the effect of magnetic fields in our analysis. Magnetic field may suppress the fragmentation in dense cores so we are excited to focus the next stage of our research on this area using the JCMT”.

This work was published: “ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): How Do Dense Core Properties Affect the Multiplicity of Protostars?” by Qiuyi Luo et al. in the Astrophysical Journal.

The work presented here was part of a wider collection of work with relevant links/publications provided below:

• JCMT SCOPE (SCUBA-2 Continuum Observations of Pre-protostellar Evolution): https://www.eaobservatory.org/jcmt/science/large-programs/scope/
• ALMASOP (ALMA Survey of Orion Planck Galactic Cold Clumps): https://ui.adsabs.harvard.edu/public-libraries/eKQmqMjaSsKk5DrvPEu-Vg
• The JCMT SPACE survey (Submilimeter Polarization and Astro-Chemistry in Earliest star formation): https://www.eaobservatory.org/jcmt/science/large-programs/space/

MAUNAKEA, HAWAIʻI –– Astronomers have unveiled the first image of the supermassive black hole at the centre of our own Milky Way galaxy. This result provides overwhelming evidence that the object is indeed a black hole and yields valuable clues about the workings of such giants, which are thought to reside at the centre of most galaxies. The image was produced by a global research team called the Event Horizon Telescope (EHT) Collaboration, using observations from a worldwide network of radio telescopes including Hawai‘i-based James Clerk Maxwell Telescope (JCMT) and the Submillimeter Array (SMA).

The image is a long-anticipated look at the massive object that sits at the very centre of our galaxy. Scientists had previously seen stars orbiting around something invisible, compact, and very massive at the centre of the Milky Way. This strongly suggested that this object — known as Sagittarius A* (Sgr A*, pronounced “sadge-ay-star”) — is a black hole, and today’s image provides the first direct visual evidence of it.

First image of the black hole at the centre of the Milky Way. Credit: EHT Collaboration

Although we cannot see the black hole itself, because it is completely dark, glowing gas around it reveals a telltale signature: a dark central region (called a “shadow”) surrounded by a bright ring-like structure. The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun.

“We were stunned by how well the size of the ring agreed with predictions from Einstein’s Theory of General Relativity,” said EHT Project Scientist Geoffrey Bower chief scientist for Hawai‘i operations from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei. “These unprecedented observations have greatly improved our understanding of what happens at the very centre of our galaxy, and offer new insights on how these giant black holes interact with their surroundings.” The EHT team’s results are being published today in a special issue of The Astrophysical Journal Letters [1].

Because the black hole is about 27,000 light-years away from Earth, it appears to us to have about the same size in the sky as a donut on the Moon. To image it, the team created the powerful EHT, which linked together eight existing radio observatories across the planet to form a single “Earth-sized” virtual telescope [2]. The EHT observed Sgr A* on multiple nights, collecting data for many hours in a row, similar to using a long exposure time on a camera.

In creating such an “Earth-sized” telescope the JCMT and SMA in Hawaii provided the most western point. Reflecting on Hawaii’s involvement in this image JCMT Head of Operations Dr Harriet Parsons noted “JCMT’s involvement in such work stretches back 15 years but Hawaii’s involvement in studying the black hole at the center of our Milky Way Galaxy has been an even longer love affair. Prior to this image, Dr. Andrea Ghez had used decades of data from the neighbouring W.M. Keck Observatory to examine orbits of stars around an invisible but massive compact object at the centre of our galaxy. This work earned her the Nobel Prize in 2020, together with Reinhard Genzel and Roger Penrose. To now have an actual image of that same black hole is incredible, and what is most exciting: this is in our home galaxy, the Milky Way.” 

The breakthrough follows the EHT collaboration’s 2019 release of the first image of a black hole, named Pōwehi (also known as M87*)[3], at the centre of the more distant Messier 87 galaxy.

Maunakea Hawaii – JCMT part of the Event Horizon Telescope, a global network of telescopes, that collected data to image the black hole at the center of the Milky Way. Image credit: W. Mongomerie, H. Parsons EAO/JCMT/EHT.

The two black holes look remarkably similar, even though our galaxy’s black hole is more than a thousand times smaller and less massive than Pōwehi [4]. “We have two completely different types of galaxies and two very different black hole masses, but close to the edge of these black holes they look amazingly similar,” says Sera Markoff, Co-Chair of the EHT Science Council and a professor of theoretical astrophysics at the University of Amsterdam, the Netherlands. “This tells us that General Relativity governs these objects up close, and any differences we see further away must be due to differences in the material that surrounds the black holes.”

This achievement was considerably more difficult than for Pōwehi, even though Sgr A* is much closer to us. EHT scientist Chi-kwan (‘CK’) Chan, from Steward Observatory and Department of Astronomy and the Data Science Institute of the University of Arizona, US, explains: “The gas in the vicinity of the black holes moves at the same speed — nearly as fast as light — around both Sgr A* and Pōwehi. But where gas takes days to weeks to orbit the larger Pōwehi, in the much smaller Sgr A* it completes an orbit in mere minutes. This means the brightness and pattern of the gas around Sgr A* was changing rapidly as the EHT Collaboration was observing it — a bit like trying to take a clear picture of a puppy quickly chasing its tail.”

The researchers had to develop sophisticated new tools that accounted for the gas movement around Sgr A*. While Pōwehi was an easier, steadier target, with nearly all images looking the same, that was not the case for Sgr A*. The image of the Sgr A* black hole is an average of the different images the team extracted, finally revealing the giant lurking at the centre of our galaxy for the first time.

Making of the image of the black hole at the centre of the Milky Way. Image credit: EHT Collaboration The Event Horizon Telescope (EHT) Collaboration has created a single image (top frame) of the supermassive black hole at the centre of our galaxy, called Sagittarius A* (or Sgr A* for short), by combining images extracted from the EHT observations. The main image was produced by averaging together thousands of images created using different computational methods — all of which accurately fit the EHT data. This averaged image retains features more commonly seen in the varied images, and suppresses features that appear infrequently. The images can also be clustered into four groups based on similar features. An averaged, representative image for each of the four clusters is shown in the bottom row. Three of the clusters show a ring structure but, with differently distributed brightness around the ring. The fourth cluster contains images that also fit the data but do not appear ring-like. The bar graphs show the relative number of images belonging to each cluster. Thousands of images fell into each of the first three clusters, while the fourth and smallest cluster contains only hundreds of images. The heights of the bars indicate the relative “weights,” or contributions, of each cluster to the averaged image at top.

The effort was made possible through the ingenuity of more than 300 researchers from 80 institutes around the world that together make up the EHT Collaboration. In addition to developing complex tools to overcome the challenges of imaging Sgr A*, the team worked rigorously for five years, using supercomputers to combine and analyse their data, all while compiling an unprecedented library of simulated black holes to compare with the observations.

Scientists are particularly excited to finally have images of two black holes of very different sizes, which offers the opportunity to understand how they compare and contrast. They have also begun to use the new data to test theories and models of how gas behaves around supermassive black holes. This process is not yet fully understood but is thought to play a key role in shaping the formation and evolution of galaxies.

“Now we can study the differences between these two supermassive black holes to gain valuable new clues about how this important process works,” said EHT scientist Keiichi Asada from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei. “We have images for two black holes — one at the large end and one at the small end of supermassive black holes in the Universe — so we can go a lot further in testing how gravity behaves in these extreme environments than ever before.”

Progress on the EHT continues: a major observation campaign in March 2022 included more telescopes than ever before. The ongoing expansion of the EHT network and significant technological upgrades will allow scientists to share even more impressive images as well as movies of black holes in the near future.

Notes

[1] The Astrophysical Journal Letters publish six collaboration and four official papers on Thursday, May 12th, 2022 at 13:07 UT.  The six collaboration papers (First Sagittarius A* Event Horizon Telescope Results):

• Paper I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• Paper II. EHT and Multi-wavelength Observations, Data Processing, and Calibration
• Paper III. Imaging of the Galactic Center Supermassive Black Hole
• Paper IV. Variability, Morphology, and Black Hole Mass
• Paper V. Testing Astrophysical Models of the Galactic Center Black Hole
• Paper VI. Testing the Black Hole Metric

Alongside four additional papers:

• Selective Dynamical Imaging of Interferometric Data
• Millimeter Light Curves of Sagittarius A* Observed during the 2017 Event Horizon Telescope Campaign
• A Universal Power Law Prescription for Variability from Synthetic Images of Black Hole Accretion Flows
• Characterizing and Mitigating Intraday Variability: Reconstructing Source Structure in Accreting Black Holes with mm-VLBI

[2] The individual telescopes involved in the EHT in April 2017, when the observations were conducted, were: the Atacama Large Millimeter/submillimeter Array (ALMA), the Atacama Pathfinder Experiment (APEX), the IRAM 30-meter Telescope, the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope Alfonso Serrano (LMT), the Submillimeter Array (SMA), the UArizona Submillimeter Telescope (SMT), the South Pole Telescope (SPT). Since then, the EHT has added the Greenland Telescope (GLT), the NOrthern Extended Millimeter Array (NOEMA) and the UArizona 12-meter Telescope on Kitt Peak to its network.

ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), the U.S. National Science Foundation (NSF), and the National Institutes of Natural Sciences (NINS) of Japan, together with the National Research Council (Canada), the Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, the Associated Universities, Inc./National Radio Astronomy Observatory (AUI/NRAO) and the National Astronomical Observatory of Japan (NAOJ). APEX, a collaboration between the Max Planck Institute for Radio Astronomy (Germany), the Onsala Space Observatory (Sweden) and ESO, is operated by ESO. The 30-meter Telescope is operated by IRAM (the IRAM Partner Organizations are MPG (Germany), CNRS (France) and IGN (Spain)). The JCMT is operated by the East Asian Observatory on behalf of the Center for Astronomical Mega-Science of the Chinese Academy of Sciences, NAOJ, ASIAA, KASI, the National Astronomical Research Institute of Thailand, and organizations in the United Kingdom and Canada. The LMT is operated by INAOE and UMass, the SMA is operated by Center for Astrophysics | Harvard & Smithsonian and ASIAA and the UArizona SMT is operated by the University of Arizona. The SPT is operated by the University of Chicago with specialized EHT instrumentation provided by the University of Arizona.

The Greenland Telescope (GLT) is operated by ASIAA and the Smithsonian Astrophysical Observatory (SAO). The GLT is part of the ALMA-Taiwan project, and is supported in part by the Academia Sinica (AS) and MOST. NOEMA is operated by IRAM and the UArizona 12-meter telescope at Kitt Peak is operated by the University of Arizona.

[3] In 2019 Astronomers collaborated with renowned Hawaiian language and cultural practitioner Dr. Larry Kimura for the Hawaiian naming of the black hole located at the center of a galaxy known as Messier 87. 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.

[4] Black holes are the only objects we know of where mass scales with size. A black hole a thousand times smaller than another is also a thousand times less massive.

More Information

About Event Horizon Telescope 

The EHT consortium consists of 13 stakeholder institutes; the Academia Sinica Institute of Astronomy and Astrophysics, the University of Arizona, the Center for Astrophysics | Harvard & Smithsonian, 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, and Radboud University.

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 East Asian Observatory is a collaboration between our partner regions in China, Japan, Korea, Taiwan, Thailand, United Kingdom, Canada, Hong Kong, Vietnam, Malaysia, and Indonesia.  Click here for more information.

The East Asian Observatory wishes to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community.  We are most fortunate to have the opportunity to conduct observations from this mountain.

Links

• EHT website: https://eventhorizontelescope.org/
• Pōwehi 2019 result: https://www.eaobservatory.org/jcmt/2019/04/powehi/
• M. Keck/Andrea Ghez Nobel Prize: https://www.keckobservatory.org/nobel-prize-ghez/

Contacts

Harriet Parsons, JCMT Head of Operations, East Asian Observatory, Hilo, Hawaii

Local Media Coverage

• First image of Milky Way’s black hole produced, (Star Advertiser)
• Maunakea Observatories help astronomers capture image of Milky Way’s black hole, (Hawaii Tribune Herald)
• Maunakea Observatories help astronomers capture 1^st image of Milky Way’s huge black hole, (West Hawaii Today)
• 2 Maunakea Observatories help produce first image of black hole at center of the Milky Way, (Big Island Now)
• Black hole at center of Milky Way photographed for the first time using Mauna Kea telescopes, (Hawaii Tribune Herald)
• Maunakea telescopes helped produce the first image of Milky Way’s black hole, (Hawaii Public Radio)

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 Wang^1,2, Patrick M. Koch¹, Roberto Galván-Madrid³, Shih-Ping Lai², Hauyu Baobab Liu¹, Sheng-Jun Lin², and Kate Pattle^2,4    

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

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.

• Observational publication: First M87 Event Horizon Telescope Results. VII. Polarization of the Ring, ApJL March 24,2021
  • http://doi.org/10.3847/2041-8213/abe71e
• Theory publication: First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon, ApJL March 24, 2021
  • http://doi.org/10.3847/2041-8213/abe4de
• Related publication: Polarimetric properties of Event Horizon Telescope targets from ALMA, Goddi, Martí-Vidal, Messias, and the EHT Collaboration, ApJL March 24, 2021
  • http://doi.org/10.3847/2041-8213/abee6a

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

• West Hawaii Today
• Hawaii Tribune Herald
• Maui Now

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

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 Venusian Lower Atmosphere Haze as a Depot for Desiccated Microbial Life: A Proposed Life Cycle for Persistence of the Venusian Aerial Biosphere, Sara Seager, Janusz J. Petkowski, Peter Gao, William Bains, Noelle C. Bryan, Sukrit Ranjan and Jane Greaves, Astrobiology 2020.
• Phosphine as a Biosignature Gas in Exoplanet Atmospheres, Calar Sousa-Silva, Sara Seager, Sukrit Ranjan, Janusz Jurand Petowski, Zhuchang Zhan, Renyu Hu, and William Bains , Astrobiology VOL. 20 NO. 2 2020

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

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:

• Liu et al. “The TOP-SCOPE Survey of Planck Galactic Cold Clumps: Survey Overview and Results of an Exemplar Source, PGCC G26.53+0.17”
• Eden et al. “SCOPE: SCUBA-2 Continuum Observations of Pre-protostellar Evolution – survey description and compact source catalogue”

Contact Information:

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

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