学术报告第198期：活动星系核中极端质量比旋近事件的形成率研究

主讲人 (Speaker): 

潘震

主讲人单位 (Speaker's Institute): 

加拿大圆周理论物理研究所

邀请人 (Invited by): 

胡一鸣

时间 (Time): 

星期三, 2021/03/10 - 21:00 to 22:00

地点 (Location): 

珠海校区天琴中心1415会议室

摘要 (Abstract): 

       Extreme Mass Ratio Inspirals (EMRIs) are important sources for space-borne gravitational wave detectors, such as LISA (Laser Interferometer Space Antenna) and TianQin. Previous EMRI rate studies have focused on the ``loss cone" scenario, where stellar-mass black holes (sBHs) are scattered into highly eccentric orbits near the central massive black hole (MBH) via multi-body interaction. In this work, we calculate the rate of EMRIs of an alternative formation channel: EMRI formation assisted by the accretion flow around accreting massive black holes. In this scenario, sBHs and stars on inclined orbits are captured by the accretion disk, and then subsequently migrate towards the MBH, under the influence of density wave generation and head wind. By solving the Fokker-Planck equation incorporating both sBH-sBH/sBH-star scatterings and sBH/star-disk interactions, we find that an accretion disk usually boosts the EMRI formation rate per individual MBH by

 compared with the canonical ``loss cone" formation channel. Taking into account that the fraction of active galactic nucleus (AGNs) is , where the MBHs are expected to be rapidly accreting, we expect EMRI formation assisted by AGN disks to be an important channel for all EMRIs observed by space-borne gravitational wave detectors. These two channels also predict distinct distributions of EMRI eccentricities and orbit inclinations, which can be tested by future gravitational wave observations.

主讲人简介 (Speaker's CV): 

潘震，2018年7月至今为加拿大圆周理论物理研究所博士后研究员。2006年9月-2010年7月：中国科学技术大学物理专业学士；2010年9月-2013年7月：中国科学技术大学天体物理学专业硕士；2013年9月-2018年6月：加利福尼亚大学戴维斯分校宇宙学专业博士。主要研究领域：宇宙学、天体物理、微波背景辐射、引力波。