Photometric redshifts and k-corrections for the Sloan Digital Sky Survey Data Release 7
Article first published online: 16 FEB 2011
© 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS
Monthly Notices of the Royal Astronomical Society
Volume 413, Issue 2, pages 1395–1408, May 2011
How to Cite
O'Mill, A. L., Duplancic, F., García Lambas, D. and Sodré, Jr, L. (2011), Photometric redshifts and k-corrections for the Sloan Digital Sky Survey Data Release 7. Monthly Notices of the Royal Astronomical Society, 413: 1395–1408. doi: 10.1111/j.1365-2966.2011.18222.x
- Issue published online: 25 APR 2011
- Article first published online: 16 FEB 2011
- Accepted 2010 December 16. Received 2010 December 9; in original form 2010 August 25
- galaxies: distances and redshifts;
- galaxies: formation;
- cosmology: theory
We present a catalogue of galaxy photometric redshifts and k-corrections for the Sloan Digital Sky Survey Data Release 7 (SDSS-DR7), available on the World Wide Web. The photometric redshifts were estimated with an artificial neural network using five ugriz bands, concentration indices and Petrosian radii in the g and r bands. We have explored our redshift estimates with different training sets, thus concluding that the best choice for improving redshift accuracy comprises the main galaxy sample (MGS), the luminous red galaxies and the galaxies of active galactic nuclei covering the redshift range 0 < z≤ 0.3. For the MGS, the photometric redshift estimates agree with the spectroscopic values within rms = 0.0227. The distribution of photometric redshifts derived in the range 0 < zphot≤ 0.6 agrees well with the model predictions.
k-corrections were derived by calibration of the k-correct_v4.2 code results for the MGS with the reference-frame (z= 0.1) (g−r) colours. We adopt a linear dependence of k-corrections on redshift and (g−r) colours that provide suitable distributions of luminosity and colours for galaxies up to redshift zphot= 0.6 comparable to the results in the literature. Thus, our k-correction estimate procedure is a powerful, low computational time algorithm capable of reproducing suitable results that can be used for testing galaxy properties at intermediate redshifts using the large SDSS data base.