标题： NOAO深广域巡天中FIRST射电源的识别 显示英文标题

标题： Identifications of FIRST radio sources in the NOAO Deep-Wide Field Survey

摘要： 本文介绍了来自 FIRST（21 厘米射电天空弱源巡天）巡天的 514 个射电源在 NOAO 深度大视场巡天（NDWFS）Boötes 区域以 1 mJy 通量密度阈值的光学和近红外认证结果。利用光学（Bw、R、I）和 K 波段数据（近似限值：Bw ≈ 25.5 星等，R ≈ 25.8 星等，I ≈ 25.5 星等，K ≈ 19.4 星等），在 514 个 FIRST 射电源中有 378 个找到了光学对应体。这相当于四波段（BwRIK）的识别率为 34%，光学波段（BwRI）的识别率为 60%，I 波段的识别率为 74%。使用 hyperz 程序计算了这些源的测光红移。研究了 hyperz 中加入类星体模板谱的可能性。我们注意到，在许多情况下，测光数据与具有极短恒星形成时标的模板最为匹配，并且所识别出的星系的推断年龄强烈依赖于关于恒星形成时标的假设。所获得的红移与更亮射电源预期的 K-z 关系相当一致，但在 z<1 的 K-z 图上存在更多的离散性。 显示英文摘要

摘要： In this paper we present the results of an optical and near infrared identification of 514 radio sources from the FIRST survey (Faint Images of the Radio Sky Survey at Twenty centimeters) with a flux-density limit of 1 mJy in the NOAO Deep-Wide Field Survey (NDWFS) Bootes field. Using optical (Bw, R, I) and K band data with approximate limits of Bw ~ 25.5mag, R ~ 25.8 mag, I ~25.5 mag and K~19.4 mag, optical counterparts have been identified for 378 of 514 FIRST radio sources. This corresponds to an identification rate of 34% in four bands (BwRIK), 60% in optical bands (BwRI) and 74% in I band. Photometric redshifts for these sources have been computed using the hyperz code. The inclusion of quasar template spectra in hyperz is investigated. We note that the photometric data are, in many cases, best matched to templates with very short star-formation timescales and the inferred ages of identified galaxies depend strongly on the assumptions about the star-formation timescale. The redshifts obtained are fairly consistent with those expected from the K-z relation for brighter radio sources but there is more scatter in the K-z diagram at z<1.