The NuSTAR Extragalactic Surveys: Source Catalog and the Compton-thick Fraction in the UDS Field
The NuSTAR Extragalactic Surveys: Source Catalog and the Compton-thick Fraction in the UDS Field
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DOI：
10.3847/1538-4365/aaa83d
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发表时间：
2018-01
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通讯作者：
A. Masini;F. Civano;A. Comastri;F. Fornasini;D. Ballantyne;G. Lansbury;E. Treister;D. Alexander;P. Boorman;W. Brandt;D. Farrah;P. Gandhi;F. Harrison;R. Hickox;D. Kocevski;L. Lanz;S. Marchesi;S. Puccetti;C. Ricci;C. Saez;D. Stern;L. Zappacosta
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作者：
A. Masini;F. Civano;A. Comastri;F. Fornasini;D. Ballantyne;G. Lansbury;E. Treister;D. Alexander;P. Boorman;W. Brandt;D. Farrah;P. Gandhi;F. Harrison;R. Hickox;D. Kocevski;L. Lanz;S. Marchesi;S. Puccetti;C. Ricci;C. Saez;D. Stern;L. Zappacosta
我们展示了 UKIDSS 超深勘测 (UDS) 领域 NuSTAR 勘测的结果和源目录，弥补了 NuSTAR ECDFS 和 COSMOS 勘测在深度和面积上的差距。该调查覆盖了~0.6 deg2的视场区域，总观测时间为~1.75 Ms，半区深度为~155 ks，校正了3-24 keV的渐晕，并在2.2 ×的全带（3-24 keV）、软带（3-8 keV）和硬带（8-24 keV）半区达到灵敏度极限。 10−14 分别为 erg cm−2 s−1、1.0 × 10−14 erg cm−2 s−1 和 2.7 × 10−14 erg cm−2 s−1。在这三个波段中的至少一个波段中总共检测到了 67 个光源，其中 56 个光源具有鲁棒的光学红移，中位数为 < z> ∼ 1.1 。通过对整个样品进行宽带 (0.5–24 keV) 光谱分析并结合 NuSTAR 硬度比，我们计算了观察到的康普顿厚度 (CT; NH > 1024 cm−2) 分数。考虑到每次 NH 测量的不确定性，最终的 CT 源数量为 6.8 ± 1.2。这对应于观测到的 CT 分数 11.5% ± 2.0%，为 CT 活动星系核的固有分数提供了可靠的下限，并对宇宙 X 射线背景合成模型施加了限制。
We present the results and the source catalog of the NuSTAR survey in the UKIDSS Ultra Deep Survey (UDS) field, bridging the gap in depth and area between NuSTAR’s ECDFS and COSMOS surveys. The survey covers a ∼0.6 deg2 area of the field for a total observing time of ∼1.75 Ms, to a half-area depth of ∼155 ks corrected for vignetting at 3–24 keV, and reaching sensitivity limits at half-area in the full (3–24 keV), soft (3–8 keV), and hard (8–24 keV) bands of 2.2 × 10−14 erg cm−2 s−1, 1.0 × 10−14 erg cm−2 s−1, and 2.7 × 10−14 erg cm−2 s−1, respectively. A total of 67 sources are detected in at least one of the three bands, 56 of which have a robust optical redshift with a median of 〈 z 〉 ∼ 1.1 . Through a broadband (0.5–24 keV) spectral analysis of the whole sample combined with the NuSTAR hardness ratios, we compute the observed Compton-thick (CT; NH > 1024 cm−2) fraction. Taking into account the uncertainties on each NH measurement, the final number of CT sources is 6.8 ± 1.2. This corresponds to an observed CT fraction of 11.5% ± 2.0%, providing a robust lower limit to the intrinsic fraction of CT active galactic nuclei and placing constraints on cosmic X-ray background synthesis models.