1702.03933
The color and stellar mass dependence of small-scale galaxy clustering in SDSS-III BOSS
Law-Smith, Eisenstein
Measure the color and stellar mass dependence of clustering in spectra galaxies at 0.6<z<0.65 using data from BOSS. Greatly increase the statistical precision of the clustering measurement by using the cross-correlation of 66,657 spec galaxies to a sample of 6.6 million fainter photometric galaxies. The clustering amplitude w(R) is measured as the ratio of the mean excess number of photometric galaxies found within a specified radius annulus around the spectroscopic galaxy to that from a random photometric galaxy distribution. Recover many of the familiar trends at high S/N ratio. Find the ratio of the clustering amplitude of red and blue massive galaxies to be w_red/w_blue = 1.92±0.11 in the smallest annulus of 75-125 kpc. At the largest radii (2-4 Mpc), find ratio = 1.24±0.05. Red galaxies therefore have denser environments than their blue counterparts at z~0.625, and this effect increases with decreasing radius. Irrespective of color, find that w(R) does not obey a simple power-law relation with radius, showing a dip around 1 Mpc. Holding stellar mass fixed, find a clear differentiation between clustering in red and blue galaxies, showing that clustering is not solely determined by stellar mass. Holding color fixed, find that clustering increases with stellar mass, especially for red galaxies at small scales (more than a factor of 2 effect over 0.75 dex in stellar mass).
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