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Title

On the galaxy stellar mass function, the mass-metallicity relation and the implied baryonic mass function

Author(s)

Baldry, Ivan K.;  Glazebrook, Karl;  Driver, Simon P.

Abstract

A comparison between published field galaxy stellar mass functions (GSMFs) shows that the cosmic stellar mass density is in the range 4–8 per cent of the baryon density (assuming Ωb= 0.045 ). There remain significant sources of uncertainty for the dust correction and underlying stellar mass-to-light ratio even assuming a reasonable universal stellar initial mass function. We determine the z < 0.05 GSMF using the New York University Value-Added Galaxy Catalog sample of 49 968 galaxies derived from the Sloan Digital Sky Survey and various estimates of stellar mass. The GSMF shows clear evidence for a low-mass upturn and is fitted with a double Schechter function that has α2≃−1.6 . At masses below ∼108.5 M⊙ , the GSMF may be significantly incomplete because of missing low-surface-brightness galaxies. One interpretation of the stellar mass–metallicity relation is that it is primarily caused by a lower fraction of available baryons converted to stars in low-mass galaxies. Using this principle, we determine a simple relationship between baryonic mass and stellar mass and present an 'implied baryonic mass function'. This function has a faint-end slope, α2≃−1.9 . Thus, we find evidence that the slope of the low-mass end of the galaxy mass function could plausibly be as steep as the halo mass function. We illustrate the relationship between halo baryonic mass function → galaxy baryonic mass function → GSMF. This demonstrates the requirement for peak galaxy formation efficiency at baryonic masses ∼1011 M⊙ corresponding to a minimum in feedback effects. The baryonic-infall efficiency may have levelled off at lower masses.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Monthly Notices of the Royal Astronomical Society, Vol. 388, no. 3 (Jul 2008), pp. 945-959

Publication year

2008

Keyword(s)

Galaxies;  Galaxy evolution;  Fundamental parameters;  Haloes;  Luminosity function;  Mass function

Publisher

Blackwell Publishing

ISSN

0035-8711

Publisher URL

http://dx.doi.org/10.1111/j.1365-2966.2008.13348.x

Copyright

Copyright © 2008 The Authors. Journal compilation copyright © 2008 Royal Astronomical Society.

Additional information

The authors are grateful to Benjamin Panter for providing his stellar mass catalogue, Phil James for comments on the paper, Maurizio Salaris for BaSTI mass-to-light ratios, Rachel Somerville for halo mass function data and the anonymous referee for suggesting useful clarifications. IKB acknowledges funding from the Science and Technology Facilities Council. KG acknowledges funding from the Australian Research Council. The authors thank Michael Blanton and the authors of the NYU-VAGC for publicly releasing their catalogue derived from the SDSS. Funding for the SDSS has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Aeronautics and Space Administration, the National Science Foundation, the US Department of Energy, the Japanese Monbukagakusho and the Max-Planck Society.

Full text

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