Does Diffuse Circumnuclear Gas around Sgr A^(*) Achieve Collisional Ionization Equilibrium or Remain Non-equilibrium Ionization?

作     者：Shu Niu Fu-Guo Xie Wei Sun Li Ji Shu Niu;Fu-Guo Xie;Wei Sun;Li Ji

作者机构：Key Laboratory for Research in Galaxies and CosmologyShanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China University of Chinese Academy of SciencesBeijing 100049China Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China Key Laboratory of Dark Matter and Space AstronomyChinese Academy of SciencesNanjing 210023China 

出 版 物：《Research in Astronomy and Astrophysics》 (天文和天体物理学研究（英文版）)

年 卷 期：2023年第23卷第8期

页      面：103-116页

核心收录：

学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学] 

基　　金：supported in part by the National SKA Program of China(No.2020SKA0110102) the National Natural Science Foundation of China(NSFC,Nos.12192220 and 12192223) the Youth Innovation Promotion Association of CAS(Y202064) 

主　　题：X-rays diffuse background-galaxies active-Galaxy center-(galaxies:)quasars emission lines 

摘      要：The feeding and feedback processes at the vicinity of a supermassive black hole(BH)are essential for our understanding of the connection between supermassive BH and its host *** this work,we provide a detailed investigation,both observational and theoretical,on the diffuse(~2-20,~0.08-0.8 pc)X-ray emission around Sgr A*.Over two-decade Chandra observations are gathered to obtain highest signal-to-noise to *** find that,the line center of iron lines of the outer 8-18region,ε_(c)=6.65+0.02-0.03 keV,is comparable to that(ε_(c)=6.60+0.05-0.03 keV)of the inner 2-5*** is somewhat unexpected,since the gas temperature decreases further away from the central *** on a dynamical inflow-outflow model that considers the gas feeding by stellar winds from Wolf-Rayet stars,we calculate the X-ray spectrum based on both the conventional collisional ionization equilibrium(CIE)assumption,and the newly developed non-equilibrium ionization(NEI)*** find that,theoretically gases within~8-10remain in a CIE state,outside of this radius they will be in the NEI state.A comparison of the properties of~6.6 keV iron lines between CIE and NEI is ***,the NEI interpretation of outer region is supported by the Chandra line center ε_(c) measurements of this region.