Date: 20 October 2022, 10:00

Speaker: Youjun Lu (陆由俊)

Affiliation: NAO,CAS

Tencent/VooV Meeting ID: 973-6909-6865

Online Meeting Link: https://meeting.tencent.com/dm/ZGVDkboF0pFP

Abstract:

Dark matter occupies the majority of matter content in the universe and is probably cold (CDM). However, modifications to the standard \LambdaCDM model may be required by the small-scale observations, and dark matter may be self-interacting (SIDM) or warm (WDM). Various probes have been applied to constrain the nature of dark matter but many of them suffer from the contamination due to baryonic processes. Gravitational waves detected by LIGO/Virgo and future detectors may be gravitational lensed by galaxies and dark matter halos, and thus encode the information of dark matter. In this talk, we will briefly overview the gravitational lensing of gravitational wave, including both the strong lensing effect in the geometric optics regime and the diffractive lensing effect in the wave optics regime. We estimate the lensing effects on the gravitational wave strain by small dark matter halos with different density profiles produced in different dark matter models and talk about the detectability of these effects. We conclude that the diffractive lensing of gravitational waves from binary black  hole mergers by small dark matter halos may serve as a clean probe to the nature of dark matter.

报告人简介：

陆由俊， 国家天文台研究员。 1997年毕业于中国科学技术大学天体物理中心，获理学博士学位。1997年就职中国科学技术大学，任讲师；1999年后在美国普林斯顿大学天体物理科学系、加拿大理论天体物理研究所、美国加州大学伯克利分校天文系和圣克鲁兹分校天文系等地作访问研究。 2008年至今，就职国家天文台任研究员；2014年至今，中国科学院大学岗位教授；2016年至今，引力波天体物理研究团组首席研究员。研究领域主要涉及黑洞物理、引力波天体物理、类星体和活动星系核、星系宇宙学以及广义相对论等。