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arXiv 0811.1450astro-ph
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XMM-牛顿偶然调查。VI。X射线亮度函数

The XMM-Newton Serendipitous Survey. VI. The X-ray Luminosity Function

J. Ebrero, F. J. Carrera, M. J. Page, J. D. Silverman, X. Barcons, M. T. Ceballos, A. Corral, R. Della Ceca, M. G. Watson

摘要:

本文给出了活动星系核在软(0.5-2 keV)、硬(2-10 keV)和超硬(4.5-7.5 keV)三个能带的X射线光度函数。我们使用XMS调查以及其他高度完整的通量有限的较深和较浅的调查,在软,硬和超硬带,分别为1009,435和119源。我们已经模拟了硬和超硬源的固有吸收(NH函数),并使用极大似然拟合技术计算了所有波段的固有X射线光度函数的分析模型。我们发现,X射线光度函数(XLF)是最好的描述亮度依赖密度演化(LDDE)模型。我们的研究结果显示出良好的整体协议与以前的结果在硬带,虽然稍弱的演变。我们的模型在软带目前与其他作品在这个波段略有差异,我们现在的XLF的形状显着平坦。我们发现超硬带活动星系核的演化速度比硬带快。活动星系核在硬带和超硬带中的吸收分数依赖于X射线亮度。我们发现的证据,这部分的演化与红移在硬带,但不是在超硬带,可能是由于低的统计。我们的最佳拟合XLF表明,高亮度活动星系核完全形成早于亮度较低的活动星系核。根据反等级黑洞增长的假设,后一种来源占了宇宙吸积率和质量密度的绝大部分。

英文摘要:

We present the X-ray luminosity function of AGN in three energy bands (Soft: 0.5-2 keV, Hard: 2-10 keV and Ultrahard: 4.5-7.5 keV). We have used the XMS survey along with other highly complete flux-limited deeper and shallower surveys for a total of 1009, 435 and 119 sources in the Soft, Hard and Ultrahard bands, respectively. We have modeled the intrinsic absorption of the Hard and Ultrahard sources (NH function) and computed the intrinsic X-ray luminosity function in all bands using a Maximum Likelihood fit technique to an analytical model. We find that the X-ray luminosity function (XLF) is best described by a Luminosity-Dependent Density Evolution (LDDE) model. Our results show a good overall agreement with previous results in the Hard band, although with slightly weaker evolution. Our model in the Soft band present slight discrepancies with other works in this band, the shape of our present day XLF being significantly flatter. We find faster evolution in the AGN detected in the Ultrahard band than those in the Hard band. The fraction of absorbed AGN in the Hard and Ultrahard bands is dependent on the X-ray luminosity. We find evidence of evolution of this fraction with redshift in the Hard band but not in the Ultrahard band, possibly due to the low statistics. Our best-fit XLF shows that the high-luminosity AGN are fully formed earlier than the less luminous AGN. The latter sources account for the vast majority of the accretion rate and mass density of the Universe, according to an anti-hierarchical black hole growth scenario.

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