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 \Omega _ { b } = 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 49968 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 \alpha _ { 2 } \simeq - 1.6 .
At masses below \sim 10 ^ { 8.5 } { \cal M } _ { \odot } , 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 principal , 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 , \alpha _ { 2 } \simeq - 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 \rightarrow galaxy baryonic mass function \rightarrow GSMF .
This demonstrates the requirement for peak galaxy formation efficiency at baryonic masses \sim 10 ^ { 11 } { \cal M } _ { \odot } corresponding to a minimum in feedback effects .
The baryonic-infall efficiency may have levelled off at lower masses .