[Colloquium] Prof. Sascha Trippe(Seoul National University). Nov. 20th, 2019.

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

Speaker: Prof. Sascha Trippe (Seoul National University)

Date & Time: Nov. 20. (Wed.) 2019 4:30 PM

Place: Natural Science 1,  Room No. 31214

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, possibly including SNU’s SRAO.

[Colloquium] Prof. Sascha Trippe(Seoul National University). Nov. 20th, 2019.