Exploring the Accretion Disk Structure and X-ray Radiation of GX 17+2 Based on kHz QPOs and Cross-correlations

作     者：De-Hua Wang Cheng-Min Zhang Ya-Juan Lei De-Hua Wang;Cheng-Min Zhang;Ya-Juan Lei

作者机构：School of Physics and Electronic ScienceGuizhou Normal UniversityGuiyang 550001China CAS Key Laboratory of FASTNational Astronomical ObservatoriesBeijing 100101China School of Physical SciencesUniversity of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Radio AstronomyChinese Academy of SciencesBeijing 100101China Key Laboratory of Solar ActivityNational Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China 

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

年 卷 期：2022年第22卷第12期

页      面：239-248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 by the National Natural Science Foundation of China(Grant Nos.12163001,U1938117 and U1731238) the Guizhou Provincial Science and Technology Foundation(Grant No.1Y016)。 

主　　题：X-rays:binaries stars:neutron stars:individual(GX 17+2) accretion accretion disks 

摘      要：Applying the timing tools of kilohertz quasi-periodic oscillations(k Hz QPOs)and cross-correlations,we study the influence of the magnetosphere-disk relation on the X-ray radiation process of GX 17+2.First,as the spectral state track of X-ray emission evolves along the horizontal branch(HB),the magnetosphere-disk radii of the source derived by k Hz QPOs shrink from r~24 km to r~18 km,while its average X-ray intensities in≤10 ke V and in≥10 ke V show the opposite evolutional trends.Moreover,this branch has been detected with the anti-correlations between the low-/high-energy(e.g.,2–5 ke V/16–30 ke V)X-rays.We suggest that in HB there may exist an X-ray radiation transfer process at the disk radii near the neutron star(NS),i.e.,~5–10 km away from the surface,which probably originates from the interaction between the corona or jet with high-energy X-rays and accretion disk with low-energy X-rays.Second,as the source evolves along the normal branch(NB)and along the flaring branch(FB),their average X-ray intensities in all~2–30 ke V show the monotonously decreasing and monotonously increasing trends,respectively.In addition,these two branches are both dominated by the positive correlations between the low-and high-energy(e.g.,2–5 ke V/16–30 ke V)X-rays.Moreover,the evolution along NB is accompanied by the shrinking of the magnetosphere-disk radii from r~18 km to r~16 km.We ascribe these phenomena to that as the shrinking of the accretion disk radius,the piled up accretion matter around the NS surface may trigger the radiation that produces both the low-and high-energy X-rays simultaneously,and then form the branches of NB and FB.