PRIMUS: THE EFFECT OF PHYSICAL SCALE ON THE LUMINOSITY DEPENDENCE OF GALAXY CLUSTERING VIA CROSS-CORRELATIONS

We report small-scale clustering measurements from the PRIsm MUlti-object Survey (PRIMUS) spectroscopic redshift survey as a function of color and luminosity. We measure the real-space cross-correlations between 62,106 primary galaxies with PRIMUS redshifts and a tracer population of similar to 545,000 photometric galaxies over redshifts from z = 0.2 to z = 1. We separately fit a power-law model in redshift and luminosity to each of three independent color-selected samples of galaxies. We report clustering amplitudes at fiducial values of z = 0.5 and L = 1.5L*. The clustering of the red galaxies is similar to 3 times as strong as that of the blue galaxies and similar to 1.5 as strong as that of the green galaxies. We also find that the luminosity dependence of the clustering is strongly dependent on physical scale, with greater luminosity dependence being found between r = 0.0625 h(-1) Mpc and r = 0.25 h(-1) Mpc, compared to the r = 0.5 h(-1) Mpc to r = 2h(-1) Mpc range. Moreover, over a range of two orders of magnitude in luminosity, a single power-law fit to the luminosity dependence is not sufficient to explain the increase in clustering at both the bright and faint ends at the smaller scales. We argue that luminosity-dependent clustering at small scales is a necessary component of galaxy-halo occupation models for blue, star-forming galaxies as well as for red, quenched galaxies.