High-precision multi-band measurements of the angular clustering of X-ray sources
High-precision multi-band measurements of the angular clustering of X-ray sources
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DOI：
10.1051/0004-6361/200911670
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发表时间：
2009-04
影响因子：
6.5
通讯作者：
J. Ebrero;J. Ebrero;S. Mateos;G. Stewart;F. Carrera;M. Watson
中科院分区：
文献类型：
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作者：
J. Ebrero;J. Ebrero;S. Mateos;G. Stewart;F. Carrera;M. Watson
目标。我们的目标是研究河外偶然X射线巡天的大尺度结构，由于涉及大量的统计数据，因此具有前所未有的精度，并提供对AGN在其空间密度下降（z = 1− 2）时的环境的见解。方法.在本文中，我们提出了两点角相关函数的X射线源人口的1063 XMM-牛顿观测在银河系高纬度地区，包括高达30000个源超过天空面积的125.5度2，在三个能量带：0.5-2（软），2-10（硬），和4.5-10（超硬）千电子伏。这是有史以来用于聚类分析的最大规模的偶然X射线源调查。结果我们已经测量了我们调查的角度聚类，并在软带和硬带中发现了显著的正聚类信号（分别为10σ和15 σ），在超硬带中发现了边缘聚类检测（<1σ）。我们发现的集群强度的流量限制和集群属性之间的高硬度比（因此可能被掩盖活动星系核）和低硬度比的来源没有显着的差异。我们通过Limber方程对角聚类参数进行反投影，以计算它们的典型空间距离。由此我们推断，红移为10.1的活动星系核嵌入在暗物质晕中，其典型质量为h log MDMHi = 12.60± 0.34 h −1 M，寿命为tAGN = 3.1− 4.5× 108年。结论.我们的研究结果表明，模糊和unobscured对象共享类似的集群属性，因此他们都resi德在类似的环境中，一致的活动星系核的统一模型。推导出的活动星系核寿命较短，表明活动星系核活动可能是一个短暂的阶段，很大一部分星系在其一生中可以经历多次。
Aims. We aim to study the large-scale structure of an extragalactic serendipitous X-ray survey with unprecedented accuracy thanks to the large statistics involved, and provide insight into t he environment of AGN at the epochs when their space density declines (z∼ 1− 2). Methods. In this paper we present the two-point angular correlation function of the X-ray source population of 1063 XMM-Newton observations at high Galactic latitudes, comprising up to ∼30000 sources over a sky area of∼125.5 deg 2 , in three energy bands: 0.5-2 (soft), 2-10 (hard), and 4.5-10 (ultrahard) keV. This is the largest survey of serendipitous X-ray sources ever used for clustering analysis. Results. We have measured the angular clustering of our survey and find significant positive clustering signals in the soft and hard bands (∼10σ and∼5σ, respectively), and a marginal clustering detection in the ultrahard band (<1σ). We find dependency of the clustering strength on the flux limit and no significant di fferences in the clustering properties between sources with high hardness ratios (and therefore likely to be obscured AGN) and those with low hardness ratios. We deprojected the angular clustering parameters via Limber’s equation to compute their typical spatial leng ths. From that we have inferred that AGN at redshifts of∼1 are embedded in dark matter haloes with typical masses ofh log MDMHi≃ 12.60± 0.34 h −1 M⊙ and lifetimes of tAGN = 3.1− 4.5× 10 8 yr. Conclusions. Our results show that obscured and unobscured objects share similar clustering properties and therefore they both resi de in similar environments, in agreement with the unified model of AGN. The short AGN lifetimes derived suggest that AGN activity might be a transient phase that can be experienced several times by a large fraction of galaxies throughout their lives.