Photometric redshifts for the SDSS Data Release 12

Róbert Beck, László Dobos, Tamás Budavári, Alexander S. Szalay, I. Csabai

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

We present the methodology and data behind the photometric redshift data base of the Sloan Digital Sky Survey (SDSS) Data Release 12. We adopt a hybrid technique, empirically estimating the redshift via local regression on a spectroscopic training set, then fitting a spectrum template to obtain K-corrections and absolute magnitudes. The SDSS spectroscopic catalogue was augmented with data from other, publicly available spectroscopic surveys to mitigate target selection effects. The training set is comprised of 1976 978 galaxies, and extends up to redshift z ≈ 0.8, with a useful coverage of up to z ≈ 0.6. We provide photometric redshifts and realistic error estimates for the 208 474 076 galaxies of the SDSS primary photometric catalogue. We achieve an average bias of Δznorm = 5.84 × 10-5, a standard deviation of σ(Δznorm) = 0.0205, and a 3σ outlier rate of Po = 4.11 per cent when cross-validating on our training set. The published redshift error estimates and photometric error classes enable the selection of galaxies with high-quality photometric redshifts. We also provide a supplementary error map that allows additional, sophisticated filtering of the data.

Original languageEnglish
Pages (from-to)1371-1381
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Volume460
Issue number2
DOIs
Publication statusPublished - 2016

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education
galaxies
catalogs
data bases
estimates
outlier
regression analysis
standard deviation
estimating
templates
methodology
rate
effect
data base

Keywords

  • Catalogues
  • Galaxies: distances and redshifts
  • Methods: data analysis
  • Techniques: photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Photometric redshifts for the SDSS Data Release 12. / Beck, Róbert; Dobos, László; Budavári, Tamás; Szalay, Alexander S.; Csabai, I.

In: Monthly Notices of the Royal Astronomical Society, Vol. 460, No. 2, 2016, p. 1371-1381.

Research output: Contribution to journalArticle

Beck, Róbert ; Dobos, László ; Budavári, Tamás ; Szalay, Alexander S. ; Csabai, I. / Photometric redshifts for the SDSS Data Release 12. In: Monthly Notices of the Royal Astronomical Society. 2016 ; Vol. 460, No. 2. pp. 1371-1381.
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