Spectral Statistics and Local Luminosity Function of a Complete Hard X-Ray Sample of the Brightest Active Galactic Nuclei
Spectral Statistics and Local Luminosity Function of a Complete Hard X-Ray Sample of the Brightest Active Galactic Nuclei
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DOI：
10.1086/504155
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发表时间：
2006-06
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影响因子：
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通讯作者：
K. Shinozaki;T. Miyaji;Y. Ishisaki;Y. Ueda;Y. Ogasaka
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作者：
K. Shinozaki;T. Miyaji;Y. Ishisaki;Y. Ueda;Y. Ogasaka
我们测量了来自HEAO-1全天空目录的明亮活动星系核（AGN）的完整通量限制样本的x射线光谱特性，以研究它们的统计数据，并为硬x射线亮度函数（HXLF）的明亮端和x射线背景的AGN种群综合模型提供更大的约束。利用ASCA、XMM-Newton和/或BeppoSAX观测数据对该样品中几乎所有agn进行了光谱研究。光谱测量使我们能够构建中性吸收柱密度（log NH）分布，并为局部宇宙中被吸收（log NH[cm-2] > 21.5）和未被吸收的agn分离HXLFs。我们的结果显示了吸收和未吸收AGN的HXLF形状不同的证据，在较高的光度下，吸收AGN的HXLF比未吸收AGN的HXLF下降得更快，这与之前报道的相似。在LX-NH图中，我们在样品的高亮度、高本然吸收区（log LX[ergs -1] > 44.5和log NH[cm-2] > 21.5）中没有发现agn，如果我们假设被吸收和未被吸收的agn具有相同的HXLF形状，我们预计大约有5个agn。我们还发现，用ASCA或XMM-Newton观测到的通量比HEAO-1观测到的通量平均小0.29倍，这是对变异性幅度尺度因子为~ 2.5的源的再观测的期望。
We have measured the X-ray spectral properties of a complete flux-limited sample of bright active galactic nuclei (AGNs) from the HEAO-1 all-sky catalogs to investigate their statistics and provide greater constraints on the bright end of the hard X-ray luminosity function (HXLF) and the AGN population synthesis model of the X-ray background. Spectral studies using data from ASCA, XMM-Newton, and/or BeppoSAX observations have been made for almost all AGNs in this sample. The spectral measurements enable us to construct the neutral absorbing column density (log NH) distribution and separate HXLFs for absorbed (log NH[cm-2] > 21.5) and unabsorbed AGNs in the local universe. Our results show evidence of a difference in the shapes of the HXLFs of absorbed and unabsorbed AGNs in that the absorbed AGN HXLF drops more rapidly at higher luminosities than that of unabsorbed AGNs, similar to what has been previously reported. In the LX-NH plot we find no AGNs in the high-luminosity, high-intrinsic-absorption regime (log LX[ergs s-1] > 44.5 and log NH[cm-2] > 21.5) in our sample, in which we expect approximately five AGNs if we assume that the absorbed and unabsorbed AGNs have identical HXLF shapes. We also find that the fluxes observed with ASCA or XMM-Newton are smaller than that observed with HEAO-1 by a factor of 0.29 on average, which is expected for reobservation of sources with a factor of ∼2.5 variability amplitude scale.