SHAO Astrophysics Colloquium

Title: Retrieving the true mass of gravitational-wave sources

Speaker: Xian Chen (Peking University)

Time： 3pm, October 26 (Thursday)

Location: Lecture Hall, 3rd floor

Abstract: Retrieving the mass of a gravitational-wave (GW) source is a difficult problem because it is degenerate with redshift. In astronomy three types of redshift exist, namely cosmological, Doppler, and gravitational redshift, but the latter two are often neglected in the analysis of GW data. We study the effects of Doppler and gravitational redshifts on GWs, motivated by recent proposals that the binary black hole mergers detected by the Laser Interferometer GW Observatory (LIGO) could have happened in the vicinity of supermassive black holes. We find that they together can contribute an effective redshift as large as 1.9 < (1 + z)< 3.4. Our results imply that black holes of 10 solar masses could masquerade as much bigger ones. Distinguishing them requires simultaneous observation of GWs in both (10 − 102) Hertz and milli-Hertz bands.

Group meetings

Black hole Accretion and High-energy Astrophysics /Black Hole Feedback and Cosmic Ray Astrophysics Seminar

Location: 1608

Time: 14:00-16:00, Wednesday(Oct. 25th)

Speaker: Fulai Guo

Title: Welcome to the Multi-Messenger Era! Lessons from a Neutron Star Merger and the Landscape Ahead
https://arxiv.org/abs/1710.05931

Speaker: Hai Yang
Title: GRMHD Simulations of Magnetized Advection Dominated Accretion on a Non-Spinning Black Hole: Role of Outflows

https://arxiv.org/abs/1206.1213