活動詳細資訊 Event Information
活動詳細資訊 Event Information
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活動訊息最後更新時間 : 2017-03-15 09:23:58
開始日期 Starting Date:2017-03-22  14:00
結束日期 Ending Date:2017-03-22  15:30
會議狀態 State:確定 Definitive
主/協辦單位 Organizer:天文及天文物理研究所 Institute of Astronomy and Astrophysics
活動地點 Venue:R1203 of the Astronomy-Mathematics Building, National Taiwan University
活動備忘 Event Memo:

Abstract

In the coming months and years mm-VLBI observations of supermassive black holes using the Event Horizon Telescope (EHT), most notably of Saggitarius A* and M87, are expected to verify the existence of astrophysical black holes through detection and measurement of the black hole shadow. Although the mathematical description of a black hole shadow is straightforward, its observational appearance is strongly governed by the (thermo)dynamics and geometrical structure of the surrounding accretion flow. This accretion flow, particularly on event horizon-scales, is turbulent and time variable, and must be modelled using general-relativistic magnetohydrodynamical (GRMHD) simulations. The propagation of radiation and therefore the appearance of shadow images, spectra and lightcurves are calculated using GR radiation transport (GRRT). Here we combine GRMHD and GRRT calculations to derive observational predictions of what upcoming VLBI observations of Sagittarius A* are expected to observe, addressing questions concerning variability therein and also discussing the possibility of testing the Kerr black hole hypothesis and constraining other black hole solutions and theories of gravity.