Bibcode
Barrena, R.; Girardi, M.; Boschin, W.; Mardirossian, F.
Bibliographical reference
Astronomy and Astrophysics, Volume 540, id.A90
Advertised on:
4
2012
Journal
Citations
21
Refereed citations
20
Description
Context. The dependence of the luminosity function (LF) of cluster
galaxies on the evolutionary state of the parent cluster is still an
open question, in particular concerning the formation/evolution of the
brightest cluster galaxies. Aims: We study the bright part of the
LFs of a sample of very unrelaxed clusters ("DARC" clusters showing
evidence of major, recent mergers) and compare them to a reference
sample of relaxed clusters that span a comparable mass and redshift
range. Methods: Our analysis is based on the SDSS DR7 photometric
data of ten massive and X-ray luminous clusters (0.2 ≲ z ≲
0.3), always considering physical radii (R200 or its
fractions). We considered r' band LFs and used the color-magnitude
diagrams (r' - i', r') to clean our samples to consider red and blue
galaxies separately. Results: We find that DARC and relaxed
clusters give similar LF parameters and blue fractions. The two samples
differ in their content of bright galaxies BGs, Mr' <
-22.5. Relaxed clusters have fewer BGs, in particular when considering
the outer cluster region 0.5R200 < R < R200
(by a factor two). However, the cumulative light in BGs is similar for
relaxed and DARC samples. Conclusions: We conclude that BGs grow
in luminosity and decrease in number as the parent clusters grow
hierarchically, which agrees with a BG formation by merging with other
luminous galaxies.
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