期刊
ASTROPHYSICAL JOURNAL
卷 752, 期 2, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/752/2/154
关键词
galaxies: active; X-rays: galaxies
资金
- Ministry of Education, Culture, Sports, Science, and Technology of Japan [20740109, 21244017, 23540265]
- Grants-in-Aid for Scientific Research [21244017, 24540237, 23540268, 20740109, 23540265] Funding Source: KAKEN
We report the discovery of a candidate active galactic nucleus (AGN), 2XMM J123103.2+110648 at z = 0.13, with an X-ray spectrum represented purely by soft thermal emission reminiscent of Galactic black hole (BH) binaries in the disk-dominated state. This object was found in the second XMM-Newton serendipitous source catalog as a highly variable X-ray source. In three separate observations, its X-ray spectrum can be represented either by a multicolor disk blackbody model with an inner temperature of kT(in) approximate to 0.16-0.21 keV or a Wien spectrum Comptonized by an optically thick plasma with kT approximate to 0.14-0.18 keV. The soft X-ray luminosity in the 0.5-2 keV band is estimated to be (1.6-3.8) x 10(42) erg s(-1). Hard emission above similar to 2 keV is not detected. The ratio of the soft to hard emission is the strongest among AGNs observed thus far. Spectra selected in high/low-flux time intervals are examined in order to study spectral variability. In the second observation with the highest signal-to-noise ratio, the low-energy (below 0.7 keV) spectral regime flattens when the flux is high, while the shape of the high-energy part (1-1.7 keV) remains unchanged. This behavior is qualitatively consistent with being caused by strong Comptonization. Both the strong soft excess and spectral change consistent with Comptonization in the X-ray spectrum imply that the Eddington ratio is large, which requires a small BH mass (smaller than similar to 10(5) M-circle dot).
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据