Chandra Observation of Point Sources in the X-Ray Elliptical Galaxy NGC 1407

作     者：Zhong-LiZhang Hai-GuangXu 

作者机构：NationalAstronomicalObservatoriesChineseAcademyofSciencesBeijing100012 DepartmentofPhysicsShanghaiJiaoTongUniversityShanghai200030 

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：2004年第4卷第3期

页      面：221-230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 

主　　题：binaries: close galaxies: elliptical and lenticular galaxies: individual:NGC 1407 X-rays: binaries X-rays: galaxies 

摘      要：With the Chandra pointing observation of about 50 ks, we have detected 41 point sources in the X-ray relatively faint elliptical galaxy NGC 1407, most of which appear to be low mass X-ray binaries. In luminosity flux units, these resolved point sources contribute about 17.8 % of the total emission of the galaxy in 0.3–10 keV. Of the remaining diffuse emission, about 53.4 % (or 43.9 % of total) may arise from unresolved point sources. We find six ultraluminous X-ray sources with luminosities above 1039 erg s?1. This number is less than has been found in NGC 720, but more than in NGC 4697 and NGC 1553, so suggesting a possible correlation between the number of ULXs and the total X-ray luminosity of early-type galaxies. A central point-like source is detected whose luminosity (2.36 ± 0.14×1039 erg s?1) is the highest among all resolved sources. However, because of its relatively low hardness ratio, we speculate that it is not likely to be a low luminosity AGN.