Title: Supermassive black holes in quasars for the Hubble tension

Speaker: Jian-Min Wang

Institute: Institute of High Energy Physics, Chinese Academy of Sciences

Host: Mouyuan Sun

Time: 16:00-17:30, Tuesday, March 30

Location: Physics Building 552

Abstract:

One supermassive black hole (SMBH) has been found in the center of Milky Way, which was awarded the Nobel Physics Prize in 2020. Quasars as monsters in the Universe are known to contain accreting SMBHs from their surroundings in galactic nuclei. Optical and ultraviolet spectra of quasars are characterized by broad emission lines with full-width-half-maximum of a few 1000km/s, which is called as broad-line region (BLR). Thanks are given to GRAVITY/VLTI for its powerful spatial resolution of the BLR of the first quasar 3C 273, and its angular size was measured, recently. In the meanwhile, reverberation mapping (RM) campaign is able to accurately measure the linear size of the broad-line region. Joint analysis of GRAVITY and RM data allows to have both the distances and SMBH mass simultaneously, providing a geometric measurement of cosmic distances. This accurate measurement is totally different the classical tools, such as Cepheid stars, type I supernovae and baryon acoustic oscillation. This will greatly help solve the Hubble tension.

Bio:

中国科学院高能物理研究所研究员。 1987年毕业于国防科学技术大学应用物理系， 1995年在中国科学技术大学天体物理中心获博士学位， 1999年入选中国科学院“ 人才计划” ， 2003年获国家杰出青年科学基金。 曾获德国A.V. Humboldt基金， 在Tuebingen大学、 京都大学、 以色列Tel Aviv大学工作。 目前， 主要研究兴趣集中在:1) 暗物质吸积与巨型黑洞的形成; 2) 活动星系核统一模型: 结构和演化; 3) 巨型黑洞活动的反馈和与星系形成; 4) 基于海量大样本数据研究黑洞演化及其宇宙学效应等领域。