The large area KX quasar catalogue – I. Analysis of the photometric redshift selection and the complete quasar catalogue
The large area KX quasar catalogue – I. Analysis of the photometric redshift selection and the complete quasar catalogue
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DOI：
10.1111/j.1365-2966.2012.21427.x
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发表时间：
2012-06
影响因子：
4.8
通讯作者：
N. Maddox;P. Hewett;C. Péroux;D. Nestor;L. Wisotzki
中科院分区：
文献类型：
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作者：
N. Maddox;P. Hewett;C. Péroux;D. Nestor;L. Wisotzki
本文介绍了对发光类星体进行大面积、~ 600°2 k波段限通量光谱调查的结果。该调查利用了UKIRT红外深空调查（UKIDSS）大面积调查（LAS）在斯隆数字巡天（SDSS）足迹范围内的天空区域。所有类星体相对于银河系恒星的k波段过剩（KX）与光度红移/分类方案相结合，用于识别光谱后续观测的候选类星体。本研究中的数据将能够为E(B−V)≤0.5等尘埃染红的发光类星体的比例提供新的约束。光谱样本分别使用K波段（14.0≤K≤16.6）和SDSS i波段（i = 19.5, 19.7和22.0）来定义，天空面积分别为287,150和196度2。该调查包括来自SDSS的bb303200个已知类星体和来自KX选择的250多个额外确认的类星体。在红移区间1.0≤z≤3.5的类星体子样本中，有1152个来自SDSS的星体和172个额外的kx选择类星体。对于已知的SDSS类星体，类星体的选择完成了95%，效率为95%，很大程度上与红移和i波段星等无关。kx选择的新类星体的特性证实了SDSS类星体选择的红移依赖性有效性，并提供了一个经历中度尘埃湮灭的发光类星体样本。该目录代表了朝着组装一个定义明确的发光类星体样本迈出的重要一步，该样本可用于研究类星体在其宿主星系或由于中间吸收线系统而经历中等程度的尘埃消退的特性。
The results of a large area, ∼600 deg2, K-band flux-limited spectroscopic survey for luminous quasars are presented. The survey utilizes the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) in regions of sky within the Sloan Digital Sky Survey (SDSS) footprint. The K-band excess (KX) of all quasars with respect to Galactic stars is exploited in combination with a photometric redshift/classification scheme to identify quasar candidates for spectroscopic follow-up observations. The data contained within this investigation will be able to provide new constraints on the fraction of luminous quasars reddened by dust with E(B − V) ≤ 0.5 mag. The spectroscopic sample is defined using the K-band, 14.0 ≤ K ≤ 16.6, and SDSS i-band limits of i = 19.5, 19.7 and 22.0 over sky areas of 287, 150 and 196 deg2, respectively. The survey includes >3200 known quasars from the SDSS and more than 250 additional confirmed quasars from the KX selection. A well-defined subsample of quasars in the redshift interval 1.0 ≤ z ≤ 3.5 includes 1152 objects from the SDSS and 172 additional KX-selected quasars. The quasar selection is >95 per cent complete with respect to known SDSS quasars and >95 per cent efficient, largely independent of redshift and i-band magnitude. The properties of the new KX-selected quasars confirm the known redshift-dependent effectiveness of the SDSS quasar selection and provide a sample of luminous quasars experiencing intermediate levels of extinction by dust. The catalogue represents an important step towards the assembly of a well-defined sample of luminous quasars that may be used to investigate the properties of quasars experiencing intermediate levels of dust extinction within their host galaxies or due intervening absorption line systems.