Optical Identifications of Companion Soft X-ray Sources of Mrk 231

作     者：HongWu Zu-GanDeng Xiao-YangXia 

作者机构：NationalAstronomicalObservatoriesChineseAcademyofSciencesBeijing100012 GraduateSchoolChineseAcademyofSciencesBeijing100080 DepartmentofPhysicsTianjinNormalUniversity300074Tianjin 

出 版 物：《Chinese Journal of Astronomy and Astrophysics》 (中国天文和天体物理学报（英文版）)

年 卷 期：2001年第1卷第6期

页      面：501-506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：The BATC Survey is supPOrted be the Chinese Academy of Sciences the National Natural Science Foundation of China This wo 

主　　题：galaxies: individual (Mrk 231)   X rays: galaxies   quasars 

摘      要：We present optical identification results for four ROSAT PSPC soft X-ray companions of Mrk 231 based on the deep BATC 6660 A-band image and the optical spectra obtained by the 60/90cm Schmidt telescope and the 2.16 m telescope at the Xinglong Station, NAOC. Three optical counterparts are quasars with redshifts z 1 and the remaining X-ray source is probably a background galaxy cluster. Therefore, none of these soft X-ray companions are physically connected with the central X-ray source Mrk 231. Incorporating the previous results of Arp 220 and Mrk 273 (Xia et al. 1998, 1999), we suggest that the apparent soft X-ray associations with ULIRGs are chance coincidence in most cases.