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

Date Published:

February 1, 2017


We measure the color and stellar mass dependence of clustering inspectroscopic galaxies at 0.6 < z < 0.65 using data from theBaryon Oscillation Spectroscopic Survey component of the Sloan DigitalSky Survey. We greatly increase the statistical precision of ourclustering measurements by using the cross-correlation of 66,657spectroscopic galaxies to a sample of 6.6 million fainter photometricgalaxies. The clustering amplitude w(R) is measured as the ratio of themean excess number of photometric galaxies found within a specifiedradius annulus around a spectroscopic galaxy to that from a randomphotometric galaxy distribution. We recover many of the familiar trendsat high signal-to-noise ratio. We find the ratio of the clusteringamplitudes of red and blue massive galaxies to be{w}{red}/{w}{blue}=1.92+/- 0.11 in our smallestannulus of 75-125 kpc. At our largest radii (2-4 Mpc), wefind {w}{red}/{w}{blue}=1.24+/- 0.05. Red galaxiestherefore have denser environments than their blue counterparts at z˜ 0.625, and this effect increases with decreasing radius.Irrespective of color, we find that w(R) does not obey a simplepower-law relation with radius, showing a dip around 1 Mpc. Holdingstellar mass fixed, we find a clear differentiation between clusteringin red and blue galaxies, showing that clustering is not solelydetermined by stellar mass. Holding color fixed, we find that clusteringincreases with stellar mass, especially for red galaxies at small scales(more than a factor of 2 effect over 0.75 dex in stellar mass).