The abundance and colours of galaxies in high-redshift clusters in the cold dark matter cosmology
High-redshift galaxy clusters allow us to examine galaxy formation in extreme environments. Here we compile data for 15 z > 1 galaxy clusters to test the predictions from a state-of-the-art semi-analytical model of galaxy formation. The model gives a good match to the slope and zero-point of the cluster red sequence. The model is able to match the cluster galaxy luminosity function at faint and bright magnitudes, but underestimates the number of galaxies around the break in the cluster luminosity function. We find that simply assuming a weaker dust attenuation improves the model predictions for the cluster galaxy luminosity function, but worsens the predictions for the red sequence at bright magnitudes. Examination of the properties of the bright cluster galaxies suggests that the default dust attenuation is large due to these galaxies having large reservoirs of cold gas as well as small radii. We find that matching the luminosity function and colours of high-redshift cluster galaxies, whilst remaining consistent with local observations, poses a challenge for galaxy formation models.
Additional Information© 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2015 November 17. Received 2015 November 3; in original form 2015 February 17. First published online December 24, 2015. We thank the referee for a thorough report with many useful and constructive comments. Thanks go to Rene Fassbender, Chris Lidman, Adam Stanford, Veronica Strazzullo and Gregory Snyder for provision of their data. In addition, we thank Begoña Ascaso, James Bartlett, Andrea Biviano, Stefano Borgani, Mark Brodwin, Alberto Cappi, Anthony Gonzalez, Sophie Maurogordato, Pierluigi Monaco, David Murphy and Adam Stanford for many useful and productive discussions and suggestions. This work was motivated by feedback from members of the Euclid Consortium Galaxy Clusters Science Working Group following the provision of galaxy mock catalogues based upon the GALFORM model. VGP acknowledges support from a European Research Council Starting Grant (DEGAS-259586). FBA acknowledges the support of the Royal Society for a University Research Fellowship. This work was carried out on the COSMA Data Centric system at Durham University, operated by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility ([http://]www.dirac.ac.uk). This equipment was funded by a BIS National E-infrastructure capital grant ST/K00042X/1, DiRAC Operations grant ST/K003267/1 and Durham University. DiRAC is part of the National E-Infrastructure.
Published - MNRAS-2016-Merson-1681-99.pdf
Submitted - 1502.04984v3.pdf