On the stellar and baryonic mass fractions of central blue and red
  galaxies
  By means of the abundance matching technique, we infer the local stellar and
baryonic mass-halo mass (Ms-Mh and Mb-Mh) relation for central blue and red
galaxies separately in the mass range Ms~10^8.5-10^12.0 Msun. The observational
inputs are the SDSS central blue and red Galaxy Stellar Mass Functions reported
in Yang et al. 2009, and the measured local gas mass-Ms relations for blue and
red galaxies. For the Halo Mass Function associated to central blue galaxies,
the distinct LCDM one is used and set up to exclude: (i) the observed
group/cluster mass function (blue galaxies are rare as centers of
groups/clusters), and (ii) halos with a central major merger at resdshifts
z<0.8 (dry late major mergers destroy the disks of blue galaxies). For red
galaxies, we take the complement of this function to the total. The obtained
mean Ms-Mh and Mb-Mh relations of central blue and red galaxies do not differ
significantly from the respective relations for all central galaxies. For
Mh>10^11.5 Msun, the Ms's of red galaxies tend to be higher than those of blue
ones for a given Mh, the difference not being larger than 1.7. For Mh<10^11.5
Msun, this trend is inverted. For blue (red) galaxies: (a) the maximum value of
fs=Ms/Mh is 0.021^{+0.016}_{-0.009} (0.034{+0.026}_{-0.015}) and it is attained
atlog(Mh/Msun)~12.0 (log(Mh/Msun)~11.9); (b) fs\propto Mh (fs\propto Mh^3) at
the low-mass end while at the high-mass end, fs\propto Mh^-0.4 (fs\propto
Mh^-0.6). The baryon mass fractions, fb=Mb/Mh, of blue and red galaxies reach
maximum values of fb=0.028^{+0.018}_{-0.011} and fb=0.034^{+0.025}_{-0.014},
respectively. For Mh<10^11.3 Msun, a much steeper dependence of fb on Mh is
obtained for the red galaxies than for the blue ones. We discuss on the
differences found in the fs-Mh and fb-Mh relations between blue and red
galaxies in the light of of semi-empirical galaxy models.
