XXL-HSC: An updated catalogue of high-redshift (z~3.5) X-ray AGN in the XMM-XXL northern field. Constraints on the bright end of the soft log N-log S
XXL-HSC: An updated catalogue of high-redshift (z~3.5) X-ray AGN in the XMM-XXL northern field. Constraints on the bright end of the soft log N-log S
复制标题
XXL-HSC：XMM-XXL 北场高红移 (z~3.5) X 射线 AGN 的更新目录。
DOI：
10.1051/0004-6361/202142059
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发表时间：
2022
影响因子：
6.5
通讯作者：
Y.) et al.
中科院分区：
文献类型：
--
作者：
Pouliasis;E. (Ueda;Y.) et al.
X射线提供了一种可靠的方法来识别活动星系核（AGN）。然而，在高红移宇宙中，由于X射线活动星系核相对较低的空间密度和X射线测量覆盖的区域较小，因此X射线活动星系核的采样率很低。除了大面积的X射线测量外，重要的是要有深层的光学数据，以便找到光学对应物并确定它们的红移。在这项工作中，我们使用 最新的[0.5-2 keV]目录沿着大量新的光谱和多波长目录，包括深光学Subaru Hyper Suprime-Cam（HSC）数据，在XMM-XXL北方场建立了一个高红移（z≥ 3.5）X射线选择的活动星系核样本，达到了 1.26兆的星等极限。我们选择了所有光谱证实的活动星系核，并用高红移候选者HSCg- andr-补充这个样本。乐队退出者为了证实这些脱落现象，我们利用光谱能量分布技术推导了它们的光度红移。我们获得了54个高z源的样本（28个具有spec-z），这是迄今为止该领域最大的样本（几乎是以前研究的三倍），我们估计了可能的污染和完整性。我们计算了在不同的红移箱数计数（logN-logS），并将我们的结果与以前的研究和模型进行比较。我们提供了最强的高红移活动星系核约束，但在明亮的流量（f0.5 − 2 keV> 10− 15 erg s−1cm−2）。 z ≥ 3.5，z ≥ 4和z ≥ 5的样品符合指数衰减模型，类似于在可见光波长下的模型。 我们的工作强调了利用广域X射线巡天和深层光学数据来发现高红移活动星系核的重要性。
X-rays offer a reliable method to identify active galactic nuclei (AGNs). However, in the high-redshift Universe, X-ray AGNs are poorly sampled due to their relatively low space density and the small areas covered by X-ray surveys. In addition to wide-area X-ray surveys, it is important to have deep optical data in order to locate the optical counterparts and determine their redshifts. In this work, we built a high-redshift (z≥ 3.5) X-ray-selected AGN sample in the XMM-XXL northern field using the most updated [0.5–2 keV] catalogue along with a plethora of new spectroscopic and multi-wavelength catalogues, including the deep optical Subaru Hyper Suprime-Cam (HSC) data, reaching magnitude limitsi∼ 26 mag. We selected all the spectroscopically confirmed AGN and complement this sample with high-redshift candidates that are HSCg- andr-band dropouts. To confirm the dropouts, we derived their photometric redshifts using spectral energy distribution techniques. We obtained a sample of 54 high-zsources (28 with spec-z), the largest in this field so far (almost three times larger than in previous studies), and we estimated the possible contamination and completeness. We calculated the number counts (logN-logS) in different redshift bins and compared our results with previous studies and models. We provide the strongest high-redshift AGN constraints yet at bright fluxes (f0.5 − 2 keV> 10−15erg s−1cm−2). The samples ofz≥ 3.5,z≥ 4, andz≥ 5 are in agreement with an exponential decline model similar to that witnessed at optical wavelengths. Our work emphasises the importance of using wide-area X-ray surveys with deep optical data to uncover high-redshift AGNs.