Absence of evidence is not evidence of absence: the colour-density relation at fixed stellar mass persists to z ~ 1

Author(s)

Cooper, Michael C.; Coil, Alison L.; Gerke, Brian F.; Newman, Jeffrey A.; Bundy, Kevin; Conselice, Christopher J.; Croton, Darren J.; Davis, Marc; Faber, S. M.; Guhathakurta, Puragra; Koo, David C.; Lin, Lihwai; Weiner, Benjamin J.; Willmer, Christopher N. A.; Yan, Renbin

Available versions

Abstract

We use data drawn from the DEEP2 Galaxy Redshift Survey to investigate the relationship between local galaxy density, stellar mass and rest-frame galaxy colour. At z∼ 0.9, we find that the shape of the stellar mass function at the high-mass [ log 10(M*/h−2 M⊙) > 10.1] end depends on the local environment, with high-density regions favouring more massive systems. Accounting for this stellar mass–environment relation (i.e. working at fixed stellar mass), we find a significant colour–density relation for galaxies with 10.6 < log 10(M*/h−2 M⊙) < 11.1 and 0.75 < z < 0.95. This result is shown to be robust to variations in the sample selection and to extend to even lower masses [down to log 10(M*/h−2 M⊙) ∼ 10.4]. We conclude by discussing our results in comparison to recent works in the literature, which report no significant correlation between galaxy properties and environment at fixed stellar mass for the same redshift and stellar mass domain. The non-detection of environmental dependence found in other data sets is largely attributable to their smaller sample sizes and lower sampling density, as well as systematic effects such as inaccurate redshifts and biased analysis techniques. Ultimately, our results based on DEEP2 data illustrate that the evolutionary state of a galaxy at z∼ 1 is not exclusively determined by the stellar mass of the galaxy. Instead, we show that local environment appears to play a distinct role in the transformation of galaxy properties at z > 1.

Publication year

2010

Publication type

Journal article

Source

Monthly Notices of the Royal Astronomical Society, Vol. 409, no. 1 (Nov 2010), pp. 337-345

ISSN

0035-8711

Publisher

Wiley

Copyright

Copyright © 2010 The authors. Journal compilation copyright © 2010 Royal Astronomical Society. The accepted manuscript is reproduced in accordance with the copyright policy of the publisher. The definitive publication is available at www.interscience.wiley.com.

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