伽瑪射線暴在宇宙的分佈及其演化與恆星形成率、重力波的關係

伽瑪射線暴在宇宙的分佈及其演化與恆星形成率、重力波的關係


Seminar:- Cosmological Distributions and Evolution of Gamma-ray Bursts and Their Relation to Star Formation Rate and Gravitational Waves 
 
Gamma-ray Bursts (GRBs), by virtue of their large redshifts are good candidates for probing the early universe, in particular the history of star formation rate (SFR). There have also been several attempts to use GRBs as “standard candles” for measurements of the global cosmological parameters. The achievement of these potentials requires determination of their “luminosity function” and the cosmological evolutions of their luminosities and formation rate (GRBFR). This is normally done by a forward fitting of the data to some assumed parametric model prediction, often assuming a GRBFR formation rate similar to the SFR. However, recent applications of the non-parametric methods developed by Efron and Petrosian to long GRBs by several authors have consistently shown (i) presence of strong luminosity evolution, which makes their use as standard candles problematical, and (ii) a GRBFR that deviates from SFR significantly at low redshifts. If this is also true for short GRBs, whose progenitors are believed to be neutron star-neutron star or neutron star black hole mergers, it will have profound implications for the rate and evolution of gravitational wave sources. TThe speaker will describe the results on long GRBs and the potentials of short GRBs. 
 
時間:2018.04.30(一) 10:30
地點:香港大學 莊月明物理樓522室
講者:Prof. Vahé Petrosian(Physics Department and Department of Applied Physics,
Stanford University) 
語言:英語

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#11

此活動由香港大學物理系主辦。