The Clustering of Massive Galaxies at z ~ 0.5 from the First Semester of BOSS Data

We calculate the real- and redshift-space clustering of massive galaxies at z ~ 0.5 using the first semester of data by the Baryon Oscillation Spectroscopic Survey (BOSS). We study the correlation functions of a sample of 44,000 massive galaxies in the redshift range 0.4 < z < 0.7. We present a halo-occupation distribution modeling of the clustering results and discuss the implications for the manner in which massive galaxies at z ~ 0.5 occupy dark matter halos. The majority of our galaxies are central galaxies living in halos of mass 10¹³ h ^-1 M _sun, but 10% are satellites living in halos 10 times more massive. These results are broadly in agreement with earlier investigations of massive galaxies at z ~ 0.5. The inferred large-scale bias (b ~= 2) and relatively high number density (\bar{n}=3× 10^{-4} h^3 Mpc^{-3}) imply that BOSS galaxies are excellent tracers of large-scale structure, suggesting BOSS will enable a wide range of investigations on the distance scale, the growth of large-scale structure, massive galaxy evolution, and other topics.