Issue |
A&A
Volume 468, Number 1, June II 2007
|
|
---|---|---|
Page(s) | 113 - 120 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20066859 | |
Published online | 26 March 2007 |
COMBO-17 measurements of the effect of environment on the type-dependent galaxy luminosity function
1
Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK e-mail: sphleps@mpe.mpg.de
2
Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany
3
Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
4
Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
5
Institut für Astrophysik, Leopold-Franzens-Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
Received:
1
December
2006
Accepted:
16
March
2007
We have developed a method to calculate overdensities in multicolour
surveys, facilitating a direct comparison of the local density contrast
measured using galaxy samples that have different redshift error
distributions, i.e. for red and blue, or bright and faint galaxies,
respectively. We calculate overdensities in small redshift slices
(, which at
corresponds roughly to
Mpc) for 9176 galaxies with
,
, and
, in three COMBO-17
fields (measuring
each). The mean redshift errors of this sample are
approximately
. In the Chandra
Deep Field South we identify a
region that is underdense by almost a factor 2 compared to the other two
fields in the same redshift range (
). This can be
used for an investigation of the variation of the colour-dependent luminosity
function with environment: We calculate the luminosity function in this
redshift range for red
sequence and blue cloud galaxies (as defined by
Bell et al. 2004)
in each of the fields
separately. While the luminosity function of the blue galaxies remains
unaffected by different density contrasts, the luminosity function of
the red galaxies clearly has a
more positive faint-end slope in the
Chandra Deep Field South as compared to the other two
COMBO-17 fields. The underdensity there is thus mainly
due to a deficiency of faint red
galaxies. This result is in qualitative agreement with the trends seen at
,
e.g. in the 2dFGRS (Croton et al. 2005),
or in the SDSS (Zandivarez et al. 2006).
Key words: cosmology: large-scale structure of Universe / galaxies: evolution
© ESO, 2007
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