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arXiv 1301.0190astro-ph.HEastro-ph.GA
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对天炉座矮星系中X射线源的XMM-牛顿搜索

An XMM-Newton search for X-ray sources in the Fornax dwarf galaxy

A. A. Nucita, L. Manni, F. De Paolis, D. Vetrugno, G. Ingrosso

摘要:

我们报告的结果,一个深档案XMM牛顿观测的天炉座球状星系,我们分析的目的是充分表征X射线源人口(在大多数情况下可能是背景活动星系核)检测到的目标。与现有数据库的交叉相关使我们能够找到一个可能与属于该星系的变星有关的源。我们还在天炉座球状星团GC 3和GC 4附近寻找X射线源,发现两个源可能与各自的星团有关。深层X射线观测也适合于寻找预计位于星系中心的中等质量黑洞(质量为$\simeq 10^{4}$ M $_{\odot}$)。在天炉座的情况下,这种搜索是非常困难的,因为星系的重心是不好的约束,因为在光学表面亮度观察到的大不对称。由于我们不能确定存在一个X射线对应的假定的黑洞,我们把限制只对吸积参数。特别是,我们发现,相应的吸积效率的上限,相对于爱丁顿光度,低至几个$10^{-5}$。

英文摘要:

We report the results of a deep archive XMM-Newton observation of the Fornax spheroidal galaxy that we analyzed with the aim of fully characterizing the X-ray source population (in most of the cases likely to be background active galactic nuclei) detected towards the target. A cross correlation with the available databases allowed us to find a source that may be associated with a variable star belonging to the galaxy. We also searched for X-ray sources in the vicinity of the Fornax globular clusters GC 3 and GC 4 and found two sources probably associated with the respective clusters. The deep X-ray observation was also suitable for the search of the intermediate-mass black hole (of mass $\simeq 10^{4}$ M$_{\odot}$) expected to be hosted in the center of the galaxy. In the case of Fornax, this search is extremely difficult since the galaxy centroid of gravity is poorly constrained because of the large asymmetry observed in the optical surface brightness. Since we cannot firmly establish the existence of an X-ray counterpart of the putative black hole, we put constraints only on the accretion parameters. In particular, we found that the corresponding upper limit on the accretion efficiency, with respect to the Eddington luminosity, is as low as a few $10^{-5}$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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