Deconstructing the galaxy stellar mass function with UKIDSS and CANDELS: The impact of colour, structure and environment

Alice Mortlock, Christopher J. Conselice, William G. Hartley, Ken Duncan, Caterina Lani, Jamie R. Ownsworth, Omar Almaini, Arjen Van Der Wel, Kuang Han Huang, Matthew L N Ashby, S. P. Willner, Adriano Fontana, Avishai Dekel, Anton M. Koekemoer, Harry C. Ferguson, Sandra M. Faber, Norman A. Grogin, Dale D. Kocevski

Research output: Contribution to journalArticlepeer-review

Abstract

We combine photometry from the Ultra Deep Survey (UDS), Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) UDS and CANDELS the Great Observatories Origins Deep Survey-South (GOODS-S) surveys to construct the galaxy stellar mass function probing both the low- and high-mass end accurately in the redshift range 0.3 < z < 3. The advantages of using a homogeneous concatenation of these data sets include meaningful measures of environment in the UDS, due to its large area (0.88 deg2), and the high-resolution deep imaging in CANDELS (H160 > 26.0), affording us robust measures of structural parameters. We construct stellar mass functions for the entire sample as parametrized by the Schechter function, and find that there is a decline in the values of ϕ and of α with higher redshifts, and a nearly constant M* up to z ~ 3. We divide the galaxy stellar mass function by colour, structure, and environment and explore the links between environmental overdensity, morphology, and the quenching of star formation. We find that a double Schechter function describes galaxies with high Sérsic index (n > 2.5), similar to galaxies which are red or passive. The low-mass end of the n > 2.5 stellar mass function is dominated by blue galaxies, whereas the high-mass end is dominated by red galaxies. This shows that there is a possible link between morphological evolution and star formation quenching in high mass galaxies, which is not seen in lower mass systems. This in turn suggests that there are strong mass-dependent quenching mechanisms. In addition, we find that the number density of high-mass systems is elevated in dense environments, suggesting that an environmental process is building up massive galaxies quicker in over densities than in lower densities.

Original languageEnglish
Pages (from-to)2-24
Number of pages23
JournalMonthly Notices of the Royal Astronomical Society
Volume447
Issue number1
DOIs
Publication statusPublished - 20 Nov 2014

Keywords

  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: luminosity function
  • Galaxies: structure
  • Mass function

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