本文章最後由 iheby 於 2016-11-29 19:05 編輯
潮汐崩潰事件作為超愛丁頓極限光度黑洞吸積的探測器 @香港科技大學物理學系
SEMINAR:- Tidal Disruption Events as a Probe of Super-Eddington Accretion onto Black Holes
The tidal disruption of a star by a massive black hole provides a unique opportunity for us to understand the physics of accretion onto black holes. So far about 50 tidal disruption events (TDEs) have been detected using X-ray, UV, optical and radio telescopes. In the first few months of the burst, the rate that stellar materials are supplied to the black hole can greatly exceed the Eddington accretion rate, giving us a perfect window to peek into super-Eddington accretion. The understanding of super-Eddington accretion, such as whether the Eddington luminosity limit can be violated, has important implications for black hole growth and galaxy evolution in the early universe. In this talk, the speaker will first give a brief summary of the observational status of TDEs. Then she will give an introduction to the TDE physics, and present our theoretical calculations on what parameters of the black hole and star can make super-Eddington accretion happen. Lastly, the speaker will talk about our ongoing general relativistic radiation magnetohydrodynamics simulations of super Eddington accretion disks in the context of TDEs. Results from these simulations can explain some previously poorly understood observational properties of TDEs, and can be applied to study other astrophysical systems such as active galactic nuclei and X-ray binaries.
時間：2016.11.23(二) 15:00 ~ 16:00
地點：香港科技大學1504室(Lifts 25-26)
講者：戴麗心 博士 Dr. Jane DAI (University of Maryland, College Park, USA)
語言：英語
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從模擬大型強子對撞機黑洞事件為大額外維度設限 @香港科技大學高等研究院
SEMINAR:- Bounds on Large Extra Dimensions from the Simulation of Black Hole Events at the LHC
Large extra dimensions were originally proposed to solve the hierarchy problem of the Standard Model of elementary particle physics. The presence of large extra dimensions dilutes gravity, lowering the Planck scale. If large extra dimensions exist and they are large enough, the Planck scale may be as low as a few TeV’s, so that the hierarchy problem is solved. A smaller Planck scale will bring about numerous phenomenological consequences; in particular, microscopic black holes may be produced in high-energy particle collisions at this energy scale. The decay of black holes, via the Hawking effect, into elementary particles enables the detection of the black hole events, which can be used to infer the existence of large extra dimensions. In this talk, the speaker will present the simulation of microscopic black hole formation at the Large Hadron Collider with the black hole event generator CATFISH, and comparison on the simulation results with the experimental data published by the Compact Muon Solenoid collaboration in 2013 at a center of mass energy of 8 TeV. The absence of observed black hole events in the experimental data allows researchers to set lower bounds on the Planck scale and black hole masses for a number (3 - 6) of large extra dimensions. He will also introduce the physics of microscopic black holes and present the various bounds related to the black hole physics.
時間：2016.11.29(二) 14:00
地點：香港科技大學 李兆基校園 盧家驄薈萃樓 賽馬會高等研究院4042室
講者：Dr Shaoqi Hou (中國武漢華中科技大學)
語言：英語
免費會議，歡迎參加
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