COSMOS PHOTOMETRIC REDSHIFTS WITH 30-BANDS FOR 2-deg2
COSMOS PHOTOMETRIC REDSHIFTS WITH 30-BANDS FOR 2-deg2
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DOI：
10.1088/0004-637x/690/2/1236
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发表时间：
2008-09
期刊：
影响因子：
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通讯作者：
O. Ilbert;P. Capak;M. Salvato;H. Aussel;H. McCracken;D. Sanders;N. Scoville;J. Kartaltepe;S. A
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文献类型：
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作者：
O. Ilbert;P. Capak;M. Salvato;H. Aussel;H. McCracken;D. Sanders;N. Scoville;J. Kartaltepe;S. A
我们提出了准确的光度红移（photo-z）在2-deg 2 COSMOS领域。红移是用30个宽、中、窄波段计算的，涵盖了紫外（银河演化探测器）、可见近红外（斯巴鲁、加拿大-法国-夏威夷望远镜（CFHT）、英国红外望远镜和国家光学天文台）和中红外（斯皮策/IRAC）。使用χ2模板拟合方法（Le Phare），并用来自甚大望远镜可见光多目标摄谱仪和凯克河外深成像多目标摄谱仪的大型光谱样本进行校准。我们开发并实现了一种新的方法，该方法考虑了发射线（[O ii]，Hβ，Hα和Lyα）对光谱能量分布（SED）的贡献。发射谱线的处理将photo-z精度提高了2.5倍。导出的photo-z与4148光谱红移的比较（即，Δz = zs-zp）表示在i+AB < 22.5时的色散，比COSMOS、CFHT Legacy Survey和Classifying Object by Medium-Band Observations-17巡天中的早期photo-z精确2-6倍。在较暗的星等i+AB < 24和z < 1.25时，精度为。深度近红外和红外阵列相机覆盖范围使photo-z能够扩展到z 2，尽管精度较低（i+AB 24）。导出了大星等选择样品的红移分布，发现中位红移范围为zm = 0.66（22 < i+AB < 22.5）~ zm = 1.06（24.5 < i+AB < 25）。在i+AB < 26.0时，多波长宇宙星表包括大约607，617个天体。COSMOS-30 photo-z使这一巡天能够充分利用于高红移星系和大尺度结构演化的研究。
We present accurate photometric redshifts (photo-z) in the 2-deg2 COSMOS field. The redshifts are computed with 30 broad, intermediate, and narrowbands covering the UV (Galaxy Evolution Explorer), visible near-IR (NIR; Subaru, Canada–France–Hawaii Telescope (CFHT), United Kingdom Infrared Telescope, and National Optical Astronomy Observatory), and mid-IR (Spitzer/IRAC). A χ2 template-fitting method (Le Phare) was used and calibrated with large spectroscopic samples from the Very Large Telescope Visible Multi-Object Spectrograph and the Keck Deep Extragalactic Imaging Multi-Object Spectrograph. We develop and implement a new method which accounts for the contributions from emission lines ([O ii], Hβ, Hα, and Lyα) to the spectral energy distributions (SEDs). The treatment of emission lines improves the photo-z accuracy by a factor of 2.5. Comparison of the derived photo-z with 4148 spectroscopic redshifts (i.e., Δz = zs − zp) indicates a dispersion of at i+AB < 22.5, a factor of 2–6 times more accurate than earlier photo-z in the COSMOS, CFHT Legacy Survey, and the Classifying Object by Medium-Band Observations-17 survey fields. At fainter magnitudes i+AB < 24 and z < 1.25, the accuracy is . The deep NIR and Infrared Array Camera coverage enables the photo-z to be extended to z ∼ 2, albeit with a lower accuracy ( at i+AB ∼ 24). The redshift distribution of large magnitude-selected samples is derived and the median redshift is found to range from zm = 0.66 at 22 < i+AB < 22.5 to zm = 1.06 at 24.5 < i+AB < 25. At i+AB < 26.0, the multiwavelength COSMOS catalog includes approximately 607,617 objects. The COSMOS-30 photo-z enables the full exploitation of this survey for studies of galaxy and large-scale structure evolution at high redshift.