바로가기 메뉴
본문 바로가기
푸터 바로가기
TOP

 

Astronomy Colloquium (2021 Spring Semester)

* Date
May 13
* Speaker
Dr. Jongho Park(ASIAA Taipei)
* Title
Magnetic field structure near the event horizon of the M87 black hole
* Abstract
 

 

The first ever image of the black hole in M87, showing an asymmetric ring-like structure, was observed with the Event Horizon Telescope (EHT) in April 2017, and was published about two years ago. The black hole image in polarized light has been recently published by the EHT Collaboration (EHTC). The resolved fractional linear polarization has a maximum located in the southwest part of the ring, where it rises to the level of ∼15%. The polarization position angles are arranged in a nearly azimuthal pattern. The EHTC compared a number of images constructed from general relativistic hydrodynamic (GRMHD) simulations with the observation and was able to put a tight constraint on the physical properties of the plasma in the vicinity of the black hole. Also, the inferred magnetic field structure is consistent with a picture where there is a strong, ordered, poloidal magnetic field in the vicinity of the black hole. This magnetic field can regulate the mass accretion process, and can play a critical role in launching powerful jets. I will briefly overview the observation, data calibration and analysis, and physical interpretation of the results.
DateSpeakerTitleRemarks
Mar 11 
Mar 18 
Mar 25 
Apr 01 
Apr 08 
Apr 15KAS Spring Meeting 
Apr 22Dr. Christian Wolf
(Australian National University)
The SkyMapper Southern Survey and the bright end of the high-redshift QSO population 
Apr 29Dr. Seo-Won Chang(SNU ARC)SkyMapper Optical Follow-up of Gravitational Wave Triggers and OzGrav2.0 
May 06Prof. Otto van Koert(SNU Dept. of Mathematics)Mathematics and the three-body problem 
May 13Dr. Jongho Park(ASIAA Taipei)Magnetic field structure near the event horizon of the M87 black hole 
May 20Dr. Natascha M. Forster Schreiber(MPE Garching)Galaxy Evolution at the Peak Epoch of Cosmic Star Formation: Witnessing In-situ the Growth and Transformations of Young Galaxies 
May 27Prof. Woojin Kwon
(SNU College of Education)
Magnetic fields of star formation revealed on the intermediate and small scalesTalk in Korean
Jun 03Dr. Minju Lee(MPE Garching)Cold gas in high-redshift galaxies 
Jun 10Dr. Jongsuk Hong(KASI)Stellar dynamics – the complexity of stellar populations and their numerical interpretations 
Jun 17Prof. Kimtake Hayasaki(Chungbuk National University)Neutrino emissions from tidal disruption eventsSpecial colloquium (after end of semester)