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

Yang, 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.

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


G. Yang

Y.Q. Xue

B. Luo

W.N. Brandt

F.E. Bauer

W. Cui

X. Kong

B.D. Lehmer

J.-X. Wang

X.-B. Wu

F. Yuan

Y.-F. Yuan

H.Y. Zhou


We derive photometric redshifts (z phot) for sources in the entire (~0.4 deg2) 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 μm). 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 σNMAD = 0.029 and an outlier fraction of 5.5% (outliers are defined as sources having |zphot – zspec |/(1 + zspec ) > 0.15) for non-X-ray sources. More specifically, we obtain σNMAD = 0.024 with 2.7% outliers for sources brighter than R = 23 mag, σNMAD = 0.035 with 7.4% outliers for sources fainter than R = 23 mag, σNMAD = 0.026 with 3.9% outliers for sources having z < 1, and σNMAD = 0.034 with 9.0% outliers for sources having z > 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 σNMAD = 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.

Journal Article Type Article
Acceptance Date Oct 24, 2014
Publication Date Dec 1, 2014
Deposit Date May 15, 2015
Publicly Available Date May 27, 2015
Journal Astrophysical Journal Supplement
Print ISSN 0067-0049
Electronic ISSN 1538-4365
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 215
Issue 2
Article Number 27
Keywords Catalogs, Cosmology: observations, Galaxies: distances and redshifts, Galaxies: evolution, Galaxies: formation, Surveys.
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Published Journal Article (3.5 Mb)

Copyright Statement
© 2014. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

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