Journal Article

The stellar evolution of luminous red galaxies, and its dependence on colour, redshift, luminosity and modelling

Rita Tojeiro, Will J. Percival, Alan F. Heavens and Raul Jimenez

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 413, issue 1, pages 434-460
Published in print May 2011 | ISSN: 0035-8711
Published online April 2011 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2010.18148.x
The stellar evolution of luminous red galaxies, and its dependence on colour, redshift, luminosity and modelling

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We present a series of colour-evolution models for luminous red galaxies (LRGs) in the seventh spectroscopic data release of the Sloan Digital Sky Survey (SDSS), computed using the full-spectrum fitting code vespa on high signal-to-noise ratio stacked spectra. The colour-evolution models are computed as a function of colour, luminosity and redshift, and we do not a priori assume that LRGs constitute a uniform population of galaxies in terms of stellar evolution. By computing star formation histories from the fossil record, the measured stellar evolution of the galaxies is decoupled from the survey’s selection function, which also evolves with redshift. We present these evolutionary models computed using three different sets of stellar population synthesis (SPS) codes. We show that the traditional fiducial model of purely passive stellar evolution of LRGs is broadly correct, but it is not sufficient to explain the full-spectral signature. We also find that higher-order corrections to this model are dependent on the SPS used, particularly when calculating the amount of recent star formation. The amount of young stars can be non-negligible in some cases, and has important implications for the interpretation of the number density of LRGs within the selection box as a function of redshift. Dust extinction, however, is more robust to the SPS modelling: extinction increases with decreasing luminosity, increasing redshift and increasing ri colour. We are making the colour-evolution tracks publicly available at http://www.icg.port.ac.uk/~tojeiror/lrg_evolution/.

Keywords: surveys; galaxies: evolution; galaxies: stellar content; cosmology: observations

Journal Article.  14798 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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