[en] We test for galactic conformity at $0.2<<!--\; <\; -->z<<!--\; <\; -->1.0$ to a projected distance of 5 Mpc using spectroscopic redshifts from the PRism MUlti-object Survey (PRIMUS). Our sample consists of ∼60,000 galaxies in five separate fields covering a total of ∼5.5 square degrees, which allows us to account for cosmic variance. We identify star-forming and quiescent “isolated primary” (i.e., central) galaxies using isolation criteria and cuts in specific star formation rate. We match the redshift and stellar mass distributions of these samples to control for correlations between quiescent fraction and redshift and stellar mass. We detect a significant (>3σ) one-halo conformity signal, or an excess of star-forming neighbors around star-forming central galaxies, of ∼5% on scales of 0–1 Mpc and a 2.5σ two-halo signal of ∼1% on scales of 1–3 Mpc. These signals are weaker than those detected in the Sloan Digital Sky Survey and are consistent with galactic conformity being the result of large-scale tidal fields and reflecting assembly bias. We also measure the star-forming fraction of central galaxies at fixed stellar mass as a function of large-scale environment and find that central galaxies are more likely to be quenched in overdense environments, independent of stellar mass. However, we find that environment does not affect the star formation efficiency of central galaxies, as long as they are forming stars. We test for redshift and stellar mass dependence of the conformity signal within our sample and show that large volumes and multiple fields are required at intermediate redshift to adequately account for cosmic variance.

[en] 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 ∼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 $L=1.5L^{\ast <!--\; ???\; -->}.$ The clustering of the red galaxies is $\sim <!--\; ???\; -->3$ times as strong as that of the blue galaxies and $\sim <!--\; ???\; -->1.5$ 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 $r=0.0625h^{-<!--\; ???\; -->1}\mathrm{M}\mathrm{p}\mathrm{c}$ and $r=0.25h^{-<!--\; ???\; -->1}\mathrm{M}\mathrm{p}\mathrm{c}$, compared to the $r=0.5h^{-<!--\; ???\; -->1}\mathrm{M}\mathrm{p}\mathrm{c}$ to $r=2h^{-<!--\; ???\; -->1}\mathrm{M}\mathrm{p}\mathrm{c}$ 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.

[en] We utilize ΛCDM halo occupation models of galaxy clustering to investigate the evolving stellar mass dependent clustering of galaxies in the PRIsm MUlti-object Survey (PRIMUS) and DEEP2 Redshift Survey over the past eight billion years of cosmic time, between $0.2<<!--\; <\; -->z<<!--\; <\; -->1.2$. These clustering measurements provide new constraints on the connections between dark matter halo properties and galaxy properties in the context of the evolving large-scale structure of the universe. Using both an analytic model and a set of mock galaxy catalogs, we find a strong correlation between central galaxy stellar mass and dark matter halo mass over the range $M_{\mathrm{h}\mathrm{a}\mathrm{l}\mathrm{o}}\sim <!--\; ???\; -->{10}^{11}$–${10}^{13}{h}^{-<!--\; ???\; -->1}{M}_{\odot <!--\; ???\; -->}$, approximately consistent with previous observations and theoretical predictions. However, the stellar-to-halo mass relation and the mass scale where star formation efficiency reaches a maximum appear to evolve more strongly than predicted by other models, including models based primarily on abundance-matching constraints. We find that the fraction of satellite galaxies in halos of a given mass decreases significantly from $z\sim <!--\; ???\; -->0.5$ to $z\sim <!--\; ???\; -->0.9$, partly due to the fact that halos at fixed mass are rarer at higher redshift and have lower abundances. We also find that the $M_1/M_{\mathrm{m}\mathrm{i}\mathrm{n}}$ ratio, a model parameter that quantifies the critical mass above which halos host at least one satellite, decreases from $\approx <!--\; ???\; -->20$ at $z\sim <!--\; ???\; -->0$ to $\approx <!--\; ???\; -->13$ at $z\sim <!--\; ???\; -->0.9$. Considering the evolution of the subhalo mass function vis-à-vis satellite abundances, this trend has implications for relations between satellite galaxies and halo substructures and for intracluster mass, which we argue has grown due to stripped and disrupted satellites between $z\sim <!--\; ???\; -->0.9$ and $z\sim <!--\; ???\; -->0.5$.

[en] We present measurements of the luminosity and color-dependence of galaxy clustering at 0.2 < z < 1.0 in the Prism Multi-object Survey. We quantify the clustering with the redshift-space and projected two-point correlation functions, ξ(r_p , π) and w_p (r_p ), using volume-limited samples constructed from a parent sample of over ∼130, 000 galaxies with robust redshifts in seven independent fields covering 9 deg² of sky. We quantify how the scale-dependent clustering amplitude increases with increasing luminosity and redder color, with relatively small errors over large volumes. We find that red galaxies have stronger small-scale (0.1 Mpc h ^–1 < r_p < 1 Mpc h ^–1) clustering and steeper correlation functions compared to blue galaxies, as well as a strong color dependent clustering within the red sequence alone. We interpret our measured clustering trends in terms of galaxy bias and obtain values of b _gal ≈ 0.9-2.5, quantifying how galaxies are biased tracers of dark matter depending on their luminosity and color. We also interpret the color dependence with mock catalogs, and find that the clustering of blue galaxies is nearly constant with color, while redder galaxies have stronger clustering in the one-halo term due to a higher satellite galaxy fraction. In addition, we measure the evolution of the clustering strength and bias, and we do not detect statistically significant departures from passive evolution. We argue that the luminosity- and color-environment (or halo mass) relations of galaxies have not significantly evolved since z ∼ 1. Finally, using jackknife subsampling methods, we find that sampling fluctuations are important and that the COSMOS field is generally an outlier, due to having more overdense structures than other fields; we find that 'cosmic variance' can be a significant source of uncertainty for high-redshift clustering measurements.