The Stellar-to-Halo Mass Relation of Local Galaxies Segregates by Color

Abstract

By means of a statistical approach that combines different semi-empirical methods of galaxy-halo connection, we derive the stellar-to-halo mass relations, SHMR, of local blue and red central galaxies separately. We also constrain the fraction of halos hosting blue/red central galaxies and the occupation statistics of blue and red satellites as a function of halo mass, M h . For the observational input, we use the blue and red central/satellite galaxy stellar mass functions and two-point correlation functions in the stellar mass range of 9 <log(M * /M ⊙ )< 12. We find that: (1) the SHMR of central galaxies is segregated by color, with blue centrals having a SHMR above the one of red centrals; at log(M h /M ⊙ )∼ 12, the M * -to-M h ratio of the blue centrals is ≈ 0.05, which is ∼ 1.7 times larger than the value of red centrals. (2) The constrained scatters around the SHMRs of red and blue centrals are ≈ 0.14 and ≈ 0.11 dex, respectively. The scatter of the average SHMR of all central galaxies changes from ∼ 0.20 dex to ∼ 0.14 dex in the 11.3 <log(M h /M ⊙ )< 15 range. (3) The fraction of halos hosting blue centrals at M h = 10 11 M ⊙ is 87%, but at 2 × 10 12 M ⊙ decays to ∼ 20%, approaching to a few per cents at higher masses. The characteristic mass at which this fraction is the same for blue and red galaxies is M h ≈ 7 × 10 11 M ⊙ . Our results suggest that the SHMR of central galaxies at large masses is shaped by mass quenching. At low masses, processes that delay star formation without invoking too strong supernova-driven outflows could explain the high M * -to-M h ratios of blue centrals as compared to those of the scarce red centrals.

Stellar Mass Function of Active and Quiescent Galaxies via the Continuity Equation

“…The green solid line and shaded area illustrate the outcome when matching the total stellar mass function from the continuity equation to the overall halo mass function at z ≈ 0; note that the shaded area takes into account the uncertainty in the determination of the local stellar mass function from the continuity equation and that arising from the rather flat shape of the average M H (M ⋆ ) correlation at the high mass end. Our result is compared with the local data for early and late type galaxies by various authors, determined via weak lensing (see Mandelbaum et al 2016;Velander et al 2014;Rodriguez-Puebla et al 2015;Hudson et al 2015) and satellite kinematics (see More et al 2011;Wojtak & Mamon 2013). We stress that the abundance matching results must be confronted with the data of spheroidal galaxies for stellar masses above, and with the data of disc-dominated galaxies below, a few 10 10 M ⊙ ; this is because spheroids and discs mostly contribute to the local stellar mass function in such stellar mass ranges (see Moffett et al 2016).…”

“…Solid red line refers to quiescent galaxies at z ∼ 0. Weak lensing data are from Mandelbaum et al (2016;circles), Velander et al (2014;squares), Rodriguez-Puebla et al (2015;triangles), and Hudson et al (2015;hexagons); satellite kinematic data are from Wojtak & Mamon (2013;diamonds) and More et al (2011;pentagons); Hα data for galaxies at z ∼ 0.8 − 2.5 are from Burkert et al (2016;crosses). Blue symbols are for disc-dominated galaxies and red symbols for spheroids.…”

“…We follow previous studies based on various semiempirical methods of galaxy and halo connection (see Rodriguez-Puebla et al 2015, their Comparat et al 2017), that includes galaxy groups and clusters. This is particularly suitable when comparing with observational determinations of the star formation efficiency based on weak gravitational lensing (see references above), that integrate all the DM mass along the line of sight, including that associated to the surrounding galaxy environment.…”

The relationship between galaxy and dark matter halo size from z ∼ 3 to the present

“…We make a deliberate choice not to divide galaxies by type in our study, as there is strong evidence that star forming/disk dominated galaxies and quiescent/red galaxies have significantly different SMHM relations (e.g. Rodríguez-Puebla et al 2015). Moreover, it is possible that disk and spheroid dominated galaxies may arise from halos with different spin parameter distributions.…”

Relations between the Sizes of Galaxies and Their Dark Matter Halos at Redshifts 0 < z < 3

“…Ratio of galaxy stellar mass M * to halo virial mass M200c plotted against M200c for four low-redshift SMHM relations from the literature that depend on galaxy color or type. These were derived by abundance matching (Rodríguez-Puebla et al 2015), weak lensing (Hudson et al 2015;Mandelbaum et al 2016), or a combination of both techniques (Dutton et al 2010). Three of the SMHM relations pertain to z = 0 and one to z = 0.5 (Hudson et al 2015).…”