The XMM-Newton survey of the ELAIS-S1 field - II. Optical identifications and multiwavelength catalogue of X-ray sources
The XMM-Newton survey of the ELAIS-S1 field - II. Optical identifications and multiwavelength catalogue of X-ray sources
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ELAIS-S1 领域的 XMM-Newton 勘测 - II。
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发表时间：
2008
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通讯作者：
G. Zamorani
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作者：
C. Feruglio;F. Fiore;F. Franca;N. Sacchi;S. Puccetti;A. Comastri;S. Berta;M. Brusa;A. Franceschini;C. Gruppioni;S. Mathur;I. Matute;M. Mignoli;F. Pozzi;C. Vignali;G. Zamorani
我们展示了在 ELAIS-S1 区域中心 0.6 deg 2 的 XMM-Newton 和 Chandra 巡天中检测到的 478 个 X 射线源样本的光学识别和多波段目录。使用 R 和 IRAC 3.6 μm 波段中的偶然符合概率来识别每个 X 射线源最可能的光学/红外对应物。通过钱德拉观测获得的精确位置补充了该方法。我们能够将目录中的每个 X 射线源关联起来。其中大约 94% 在 R 波段中检测到，而其余的在 R ∼ 24.5 以下的光学波段中是空白区域，但 IRAC 在距 XMM-牛顿质心 6 �� 内检测到了近红外对应物。使用已识别的光学对应物的位置生成的多波段目录包含从 B 到 MIPS 24 μm 波段的 10 个光度波段的光度测定。光谱跟踪使我们能够确定 237 个比 R = 24 更亮的光源（样本的 50%）的红移和分类。68 个光源的可靠光度红移对光谱红移进行了补充。我们将 47% 具有光谱红移的源分类为 z = 0.1−3.5 的宽线活动星系核 (BL AGN)，而没有宽线的源 (NOT BL AGN) 约占光谱样本的 46%，最高可达 z = 2.6。剩余部分由扩展的 X 射线源和恒星表示。我们通过光谱鉴定了 F(2−10 keV)/F(R) > 8 的源中的 11 个 2 型 QSO，红移在 0.9 和 2.6 之间，2−10 keV 高光度（log L2−10 keV ≥ 43.8 erg s −1 ）和硬 X 射线颜色表明在静止帧处有大的吸收柱（log NH 高达 23.6）厘米 -2 ）。 BL AGN 平均显示蓝色光学到近红外颜色、较柔和的 X 射线颜色以及典型的光学选择 AGN 的 X 射线到光学颜色。相反，窄线源显示出更红的光学颜色、更硬的 X 射线通量比，并且涵盖更广泛的 X 射线与光学颜色。平均而言，高亮度 BL AGN 的光谱能量分布 (SED) 类似于无遮挡 AGN 的典型幂律。 NOT BL AGN 的 SED 主要由光学/近红外中的星系发射主导，并显示出中红外的上升，这表明存在被遮挡的活动核。我们研究红外到光学颜色和近红外 SED，以推断 AGN 宿主星系的特性。
We present the optical identifications and a multi-band catalogue of a sample of 478 X-ray sources detected in the XMM-Newton and Chandra surveys of the central 0.6 deg 2 of the ELAIS-S1 field. The most likely optical/infrared counterpart of each X-ray source was identified using the chance coincidence probability in the R and IRAC 3.6 μm bands. This method was complemented by the precise positions obtained through Chandra observations. We were able to associate a counterpart to each X-ray source in the catalogue. Approximately 94% of them are detected in the R band, while the remaining are blank fields in the optical down to R ∼ 24.5, but have a near-infrared counterpart detected by IRAC within 6 �� from the XMM-Newton centroid. The multi-band catalogue, produced using the positions of the identified optical counterparts, contains photometry in ten photometric bands, from B to the MIPS 24 μm band. The spectroscopic follow-up allowed us to determine the redshift and classification for 237 sources (∼50% of the sample) brighter than R = 24. The spectroscopic redshifts were complemented by reliable photometric redshifts for 68 sources. We classified 47% of the sources with spectroscopic redshift as broad-line active galactic nuclei (BL AGNs) with z = 0.1−3.5, while sources without broadlines (NOT BL AGNs) are about 46% of the spectroscopic sample and are found up to z = 2.6. The remaining fraction is represented by extended X-ray sources and stars. We spectroscopically identified 11 type 2 QSOs among the sources with F(2−10 keV)/F(R) > 8, with redshift between 0.9 and 2.6, high 2−10 keV luminosity (log L2−10 keV ≥ 43.8 erg s −1 ) and hard X-ray colors suggesting large absorbing columns at the rest frame (log NH up to 23.6 cm −2 ). BL AGNs show on average blue optical-to-near-infrared colors, softer X-ray colors and X-ray-to-optical colors typical of optically selected AGNs. Conversely, narrow-line sources show redder optical colors, harder X-ray flux ratio and span a wider range of X-ray-to-optical colors. On average the Spectral Energy Distributions (SEDs) of high-luminosity BL AGNs resemble the power-law typical of unobscured AGNs. The SEDs of NOT BL AGNs are dominated by the galaxy emission in the optical/near-infrared, and show a rise in the mid-infrared which suggests the presence of an obscured active nucleus. We study the infrared-to-optical colors and near-infrared SEDs to infer the properties of the AGN host galaxies.