The Color and Stellar Mass Dependence of Small-Scale Galaxy Clustering in SDSS-III BOSS

We measure the correlation of clustering to color and stellar mass in spectroscopic galaxies at 0.6 < z < 0.65 using data from the Baryon Oscillation Spectroscopic Survey (BOSS) component of the Sloan Digital Sky Survey (SDSS-III). The clustering strength of each spectroscopic galaxy is measured as the number of photometric galaxies found within a specified radius annulus around it. We cross-correlate 66,657 (after redshift selection) spectroscopic galaxies with 6,625,645 imaging galaxies to measure clustering coefficients ω_red and ω_blue for red and blue galaxies (defined as g — i > or < 2.35). We find the ratio of these coefficients, wred/wblue, to be 1.921 \(\pm\) 0.11 in our smallest annulus of 75-125 kpc. At our largest radii (2-4 Mpc), we find wred/wblue to be 1.243 span class="math-tex">\(\pm\)/span> 0.05. Red galaxies therefore have denser environments that their blue counterparts at span class="math-tex">\(z \approx\)/span> 0.625, and this effect heightens with decreasing radius. Irrespective of color, we find that omega; does not obey a simple power law relation with radius, showing a dip around 1 Mpc attributable to the transition from one- to two-halo regimes in HOD models. Holding mass fixed, we find a clear differentiation between clustering in red and blue galaxies, showing that clustering is not solely determined by stellar mass. Holding color fixed, we find that clustering increases with mass, and that this relationship is especially strong in red galaxies at small scales (a factor of 2 effect)./p>