射电宁静的活动星系核的光变研究进展

Research progress of radio quiet active galactic nuclei variability

一部分星系的核区存在剧烈的非恒星活动起源的多波段电磁辐射,这类星系被称为活动星系,其核心称为活动星系核.一般认为,超大质量黑洞(其质量是数百万倍乃至数百亿倍太阳质量)通过其强大的引力吸积周围气体形成的吸积盘是活动星系核的中心引擎.理解这一物理过程和测量超大质量黑洞的物理参数,对认识强引力场下的磁流体物理、超大质量黑洞的宇宙增长历史和活动星系核的反馈以及宇宙大尺度结构形成有重要的意义.多波段连续谱的光变(即光度随时间的变化行为)是活动星系核的鲜明特征,可以被用来从时域的角度测量宇宙学距离上的活动星系核的中心引擎的结构、尺寸和超大质量黑洞的质量以及自旋.本文介绍了活动星系核光变行为的基本概念,概述利用光变研究活动星系核物理过程和测量超大质量黑洞质量等方面的主要进展,并对活动星系核的光变研究领域进行展望.

A fraction of galaxies accommodate active galactic nuclei(AGNs)in their centers,which can generate luminous non-stellar multiwavelength emission.It is widely believed that AGNs are powered by the gas accretion of supermassive black holes(SMBHs),whose masses can reach several million to ten billion solar masses.Understanding the accretion physics of SMBHs as well as measuring their masses and spins greatly helps us study the magnetohydrodynamic turbulence under strong gravity,the cosmic mass growth history of SMBHs,AGN feedback,and the formation of cosmic structures.As a ubiquitous feature of AGNs,multiwavelength aperiodic luminosity variations constitute probes of sizes and structures of AGN central engines,masses and spins of SMBHs.In this review,we will introduce the fundamental astrophysics of AGN variability and show how it can be used to probe AGN astrophysical processes as well as measure SMBH masses and spins.Finally,prospects of the future research are presented.