2023 Seminars

This page lists the Seminars that were given virtually on zoom in 2023. The EAO staff would like to thank all guest speakers and encourage new astronomers/instrument specialists to give virtual talks.

March 21st, 10:00 am (HST)

Title: Infall motion with rotation of the cluster forming clump GGD12-15

Speaker: Tomomi Shimoikura, Otsuma Women’s University, Japan

Abstract: We present results of mapping observations with various molecular lines made toward GGD12-15 using the NRO 45 m telescope and JCMT. GGD12-15 is an active star-forming site embedded in the Mon R2 molecular cloud. Previous studies revealed a molecular clump with a mass of ~1000 Mo in this region. We investigated the molecular gas kinematics in the clump. The distribution of the C18O (J=3-2) emission is similar to that of a star cluster forming therein, with an elliptical shape of ~1 pc in size. There is a massive core with a radius of 0.3 pc and a mass of 530 Mo in the center of the clump. The velocity structure of the C18O (J=3-2) emission line shows two velocity components around the core, which are prominent in a position-velocity (PV) diagram along the extended structure of the clump. A velocity gradient is also observed in a PV diagram along the direction perpendicular to the axis of the extended structure of the clump. We made a simple model of a gravitationally collapsing clump and compared it with the observed data. The results suggest that the clump is collapsing with rotation.

January 18th, 10:00 am (HST)

Title: The Commensal Radio Astronomy FAST Survey (CRAFTS) – Refreshing the View of the Milky Way

Speaker: Di Li, NAOC/CAS/FAST, China

Abstract: Inspired by the Arecibo telescope, the FAST telescope has been in operation for three years as the world’s largest single-dish antenna. In GHz bands, HI and pulsars have been two primary science targets. No major telescope, including Arecibo, Parkes, GBT, etc., has realized large-scale simultaneous survey of HI and pulsars, until FAST. Facilitated by our proprietary high-cadence-CAL technique, the CRAFTS survey records pulsars, Galactic HI, HI galaxies, and transients data streams, simultaneously. CRAFTS has covered 18% of the Northern sky, achieving 1% accuracy in HI flux calibration, discovering thousands of HI galaxies, discovering 160 new pulsars including a double-neutron-star, and 6 new FRBs. I will report here a few science highlights from CRAFTS as well as related PI programs, such as the first HI-narrow-self-absorption (HINSA) Zeeman measurement (Ching et al. 2022, Nature cover),  a unified picture of the frequency evolution of FRB’s polarization (Feng et al. 2022 Science), the largest extended HI structure (Xu et al. Nature 2022), etc. I will also briefly report the current status of related JCMT programs.

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