Photometric Redshifts in the Hawaii-Hubble Deep Field-North (H-HDF-N)

TitlePhotometric Redshifts in the Hawaii-Hubble Deep Field-North (H-HDF-N)
Publication TypeJournal Article
Year of Publication2014
AuthorsYang, G, Xue, Y Q, Luo, B, Brandt, W N, Alexander, D M, Bauer, F E, Cui, W, Kong, X, Lehmer, B D, Wang, J-X, Wu, X-B, Yuan, F, Yuan, Y-F, Zhou, H Y
Keywordscatalogs, cosmology: observations, galaxies: distances and redshifts, galaxies: evolution, galaxies: formation, surveys

{We derive photometric redshifts (z $_{phot}$) for sources in the entire (\~{}0.4 deg$^{2}$) Hawaii-Hubble Deep Field-North (H-HDF-N) field with the EAzY code, based on point-spread-function-matched photometry of 15 broad bands from the ultraviolet (U band) to mid-infrared (IRAC 4.5 {$μ$}m). Our catalog consists of a total of 131,678 sources. We evaluate the z $_{phot}$ quality by comparing z $_{phot}$ with spectroscopic redshifts (z $_{spec}$) when available, and find a value of normalized median absolute deviation {$\sigma$}$_{NMAD}$ = 0.029 and an outlier fraction of 5.5% (outliers are defined as sources having |z$_{phot}$ - z$_{spec}$ |/(1 + z$_{spec}$ ) {\gt} 0.15) for non-X-ray sources. More specifically, we obtain {$\sigma$}$_{NMAD}$ = 0.024 with 2.7% outliers for sources brighter than R = 23 mag, {$\sigma$}$_{NMAD}$ = 0.035 with 7.4% outliers for sources fainter than R = 23 mag, {$\sigma$}$_{NMAD}$ = 0.026 with 3.9% outliers for sources having z łt} 1, and {$\sigma$}$_{NMAD}$ = 0.034 with 9.0% outliers for sources having z {\gt} 1. Our z $_{phot}$ quality shows an overall improvement over an earlier z $_{phot}$ work that focused only on the central H-HDF-N area. We also classify each object as a star or galaxy through template spectral energy distribution fitting and complementary morphological parameterization, resulting in 4959 stars and 126,719 galaxies. Furthermore, we match our catalog with the 2 Ms Chandra Deep Field-North main X-ray catalog. For the 462 matched non-stellar X-ray sources (281 having z $_{spec}$), we improve their z $_{phot}$ quality by adding three additional active galactic nucleus templates, achieving {$\sigma$}$_{NMAD}$ = 0.035 and an outlier fraction of 12.5%. We make our catalog publicly available presenting both photometry and z $_{phot}$, and provide guidance on how to make use of our catalog. }