Photometric Redshifts for Galaxies in the GOODS Southern Field

B. Mobasher; R. Idzi; N. Benitez; A. Cimatti; S. Cristiani; E. Daddi; T. Dahlen; M. Dickinson; T. Erben; H. C. Ferguson; M. Giavalisco; N. A. Grogin; A. M. Koekemoer; M. Mignoli; L. A. Moustakas; M. Nonino; P. Rosati; M. Schirmer; D. Stern; E. Vanzella; C. Wolf; G. Zamorani; STScI; JHU; Osservatorio Astrofisico di Arcetri; Osservatorio Astronomico di Trieste; ESO; Bonn; Osservatorio Astrofisico di Bologna; JPL; Oxford

doi:10.1086/378186

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Photometric Redshifts for Galaxies in the GOODS Southern Field

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Abstract

We use extensive multi-wavelength photometric data from the Great Observatories Origins Deep Survey (GOODS) to estimate photometric redshifts for a sample of 434 galaxies with spectroscopic redshifts in the Chandra Deep Field South. Using the Bayesian method, which incorporates redshift/magnitude priors, we estimate photometric redshifts for galaxies in the range 18 < R (AB) < 25.5, giving an rms scatter of 0.11. The outlier fraction is < 10%, with the outlier-clipped rms being 0.047. We examine the accuracy of photometric redshifts for several, special sub--classes of objects. The results for extremely red objects are more accurate than those for the sample as a whole, with rms of 0.051 and very few outliers (3%). Photometric redshifts for active galaxies, identified from their X-ray emission, have a dispersion of 0.104, with 10% outlier fraction, similar to that for normal galaxies. Employing a redshift/magnitude prior in this process seems to be crucial in improving the agreement between photometric and spectroscopic redshifts.

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B. Mobasher, R. Idzi, N. Benitez, A. Cimatti, S. Cristiani, E. Daddi, T. Dahlen, M. Dickinson, T. Erben, H. C. Ferguson, M. Giavalisco, N. A. Grogin, A. M. Koekemoer, M. Mignoli, L. A. Moustakas, M. Nonino, P. Rosati, M. Schirmer, D. Stern, E. Vanzella, C. Wolf, G. Zamorani, STScI, JHU, Osservatorio Astrofisico di Arcetri, Osservatorio Astronomico di Trieste, ESO, Bonn, Osservatorio Astrofisico di Bologna, JPL, Oxford. 2003-09-02. Photometric Redshifts for Galaxies in the GOODS Southern Field. https://doi.org/10.1086/378186

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