The BeppoSAX High-Energy Large-Area Survey. V. The Nature of the Hard X-Ray Source Population and Its Evolution
The BeppoSAX High-Energy Large-Area Survey. V. The Nature of the Hard X-Ray Source Population and Its Evolution
复制标题
BeppoSAX 高能大面积勘测。
DOI：
10.1086/339575
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
F. Pompilio
中科院分区：
文献类型：
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作者：
F. La Franca;F. Fiore;C. Vignali;A. Antonelli;A. Comastri;P. Giommi;G. Matt;S. Molendi;G. Perola;F. Pompilio
我们给出了用BeppoSAX获得的5-10keV通量极限为f5-10keV~3×10-14ergs cm-2 S-1的高能大面积探测样品的硬X射线(5-10keV)选定源的光谱鉴定。样本由118个来源组成。通过与已知来源目录的关联，已经确定了25个来源。用望远镜搜索了另外49个的光谱鉴定。13个字段的结果都是空的，R=21。有37个源被鉴定为1型活动星系核(AGN)，9个源被鉴定为2型活动星系核(AGN)。剩下的来源是五个狭窄的发射线星系，六个星系团，两个BLLac天体，一个射电星系和一颗恒星。将这些天体与ASCA和HEAO-1选择的其他硬X射线活动星系核相结合，我们发现在2-10keV波段I型活动星系核(AGN-1S)的局域光度函数可以很好地用双幂函数表示。根据纯光度演化模型[lx(Z)∝(1+z)k]，在a(σm，≃)=(1.0，0)和a(Ωm，Ωλ)=(0.3，0.7)宇宙学中，k分别为2.12和2.2 2(Ωm，Ωλ).数据显示了微弱的高红移型活动星系核1s的过剩，这是由光度相关密度演化(LDDE)很好地模拟的，类似于在软X射线中观察到的。然而，在这两种宇宙学中，统计数据都不够重要，不足以区分PLE和LDDE模型。拟合的模型表明，活动星系核1s对2-10keV X射线背景的贡献从35%到60%不等。
We present optical spectroscopic identifications of hard X-ray (5-10 keV) selected sources belonging to the High-Energy Large-Area Survey sample obtained with BeppoSAX down to a 5-10 keV flux limit of f5-10 keV ~ 3 × 10-14 ergs cm-2 s-1. The sample consists of 118 sources. There are 25 sources that have been identified through correlations with catalogs of known sources. A spectroscopic identification for 49 more has been searched for with the telescope. The results of 13 fields were empty down to R = 21. There were 37 sources identified as type 1 active galactic nuclei (AGNs) and nine as type 2 AGNs. The remaining sources are five narrow emission-line galaxies, six clusters, two BL Lac objects, one radio galaxy, and one star. Combining these objects with other hard X-ray selected AGNs from ASCA and HEAO 1, we find that the local luminosity function of type 1 AGNs (AGN 1s) in the 2-10 keV band is fairly well represented by a double power law function. There is evidence for significant cosmological evolution according to a pure luminosity evolution (PLE) model [LX(z) ∝ (1 + z)k], with k = 2.12 and 2.22 (σk ≃ 0.14) in a (Ωm, Ωλ) = (1.0, 0.0) and a (Ωm, Ωλ) = (0.3, 0.7) cosmology, respectively. The data show an excess of faint high-redshift type AGN 1s, which is well modeled by a luminosity-dependent density evolution (LDDE), similar to what is observed in soft X-rays. However, in both cosmologies, the statistics are not significant enough to distinguish between the PLE and LDDE models. The fitted models imply a contribution of AGN 1s to the 2-10 keV X-ray background from 35% up to 60%.