At the End of Space and Time: Imaging the Black Hole in M 87

Colloquium

Astronomy Colloquium (2019 Spring Semester)

* Date: May 23
* Speaker: Prof. Sascha Trippe (SNU)
* Title: At the End of Space and Time: Imaging the Black Hole in M 87
* Abstract

Supermassive black holes are the power sources of active galactic nuclei. The central black hole of Messier 87 (M 87) has an angular diameter of about 8 micro-arcsec and, due to strong gravitational lensing, a photon ring angular diameter of about 40 micro-arcsec. This size can be resolved by global radio interferometric arrays observing at frequencies of 230 GHz or higher. In April 2017, the Event Horizon Telescope (EHT) observed the black hole in M 87 for several days. The resulting image shows an asymmetric photon ring which is fully consistent with the expectations from general relativity, as tested by comparison to a large library of models from general relativistic ray tracing.The black hole mass is found to be about 6.5 billion solar masses, in good agreement with previous estimates from stellar dynamics but inconsistent with previous estimates using gas dynamics. EHT observations of M 87 are supposed to continue in spring 2020 with several additional telescopes, including SNU’s SRAO.

Date	Speaker	Title	Remarks
March 7	No Colloquium	OT to the Seminar Course
March 14	Dr. Ena Choi (Columbia Unv.)	Making Massive Elliptical Galaxies
March 21	KASI ALMA TEAM	ALMA Cycle-7 proposal Townhall meeting
March 28	Prof. Changbom Park (KIAS)	Cosmology with Large-scale Structures in the Universe
April 4	Prof. Masateru Ishiguro (SNU)	Hirayama Family and Exploration of Asteroids
April 11	No colloquium	Korean Astronomical Society Spring Meeting
April 18	Prof. Sunghoon Jung (SNU)	Seeing Dark Matter with Gravitational Waves
April 25	Dr. Z. Lucas Uhm (KASI)	Physics of Relativistic Jets in Gamma-ray Bursts in the New Era of Multi-messenger Astrophysics
May 2	Prof. Jeong-Eun Lee (Kyung Hee Univ.)	Chemistry in Star and Planet Formation	Speech in Korean
May 9	Dr. Masa Imanishi (NAOJ)	ALMA reveals a rotating dense molecular torus in NGC 1068
May 16	Dr. Pei-Ying Hsieh (ASIAA)	The Role of the Magnetic Field in the Circumnuclear Disk of the Galactic Center – Implications From 850 micron Polarization Data
May 23	Prof. Sascha Trippe (SNU)	At the End of Space and Time: Imaging the Black Hole in M 87	Special colloquium on the recent result of the Event Horizon Telescope (EHT)
May 30	Naeun Shin (SNU)	대학원생이 바라본 해외교육지원단 3기 원정대 활동
June 6	No colloquium	Memorial Day
June 13	Dr. Shinsuke Takasao (NAGOYA Univ.)	Investigating the accretion process onto young stars using 3D MHD simulations

2019 Spring semester detail