• DOI:10.1051/0004-6361/201322814
• Corpus ID: 53996913

The WIRCam Deep Survey - II. Mass selected clustering

@article{Bielby2013TheWD,
  title={The WIRCam Deep Survey - II. Mass selected clustering},
  author={Richard M Bielby and Violeta Gonzalez-Perez and Henry Joy McCracken and Olivier Ilbert and Emanuele Daddi and Olivier Le F{\`e}vre and Patrick Hudelot and Jean-Paul Kneib and Yannick Mellier and Chris J. Willott},
  journal={Astronomy and Astrophysics},
  year={2013},
  volume={568}
}

• R. Bielby, V. Gonzalez-Perez, +7 authors C. Willott
• Published 8 October 2013
• Physics
• Astronomy and Astrophysics

We present an analysis of the clustering of galaxies from z ≈ 2 to the present day
using the WIRCam Deep Survey (WIRDS). WIRDS combines deep optical data from the CFHTLS
Deep fields with its own deep near-infrared data, providing a photometric data-set over an
effective area of 2.4 deg2, from which accurate photometric redshifts and stellar
masses can be estimated. We use the data to calculate the angular correlation function for
galaxy samples split by star-formation activity, stellar mass and redshift. Using WIRDS
with its large total area and multiple fields gives a low cosmic variance contribution to
the error, which we estimate to be less than ~2.8%. Based on power-law fits, we estimate the real-space clustering
for each sample, determining clustering lengths and power-law slopes. For galaxies
selected by constant mass, we find that the clustering scale shows no evolution up to
z ≈ 2.
Splitting the galaxy sample by mass, we see a consistent trend for higher mass galaxies to
have larger clustering scales at all redshifts considered. We use our results to test the
galform semi-analytical model of galaxy formation and evolution. The observed
trends are well matched by the model galaxies for both the redshift evolution and the mass
dependence of the galaxy clustering. We split the galaxy population into passive and
star-forming populations based on rest-frame dust-corrected NUV-r colours. We find that the
passive galaxy populations show a significantly larger clustering scale at all redshifts
than the star-forming population below masses of M⋆ ~
1011 h-1 M⊙,
showing that even at z ≈
2 passive galaxies exist in denser environments than the bulk of the
star-forming galaxy population. For star-forming galaxies with stellar masses of
M⋆ ≳
1011 h-1 M⊙,
we find a clustering strength of ~8h-1 Mpc across all redshifts, comparable
to the measurements for the passive population. Additionally, for star-forming galaxies we
see that clustering strength increases for higher stellar mass systems, however little
sign of a mass dependence in passive galaxies is observed over the range in stellar mass
that is probed. Comparing our results to the model galaxy population produced by
galform, we find a qualitative good agreement between the model predictions and
the observed clustering. Finally, we investigate the connection between galaxy stellar
mass and dark matter halo mass, showing a clear correlation between the two in both the
WIRDS data and the galform predictions.