PRIMUS + DEEP2: Clustering of X-ray, Radio and IR-AGN at z~0.7

We measure the clustering of X-ray, radio, and mid-IR-selected active galactic nuclei (AGN) at 0.2 < z < 1.2 using multi-wavelength imaging and spectroscopic redshifts from the PRIMUS and DEEP2 redshift surveys, covering 7 separate fields spanning ~10 square degrees. Using the cross-correlation of AGN with dense galaxy samples, we measure the clustering scale length and slope, as well as the bias, of AGN selected at different wavelengths. Similar to previous studies, we find that X-ray and radio AGN are more clustered than mid-IR-selected AGN. We further compare the clustering of each AGN sample with matched galaxy samples designed to have the same stellar mass, star formation rate, and redshift distributions as the AGN host galaxies and find no significant differences between their clustering properties. The observed differences in the clustering of AGN selected at different wavelengths can therefore be explained by the clustering differences of their host populations, which have different distributions in both stellar mass and star formation rate. Selection biases inherent in AGN selection, therefore, determine the clustering of observed AGN samples. We further find no significant difference between the clustering of obscured and unobscured AGN, using IRAC or WISE colors or X-ray hardness ratio.

PRIMUS: Infrared and X-ray AGN Selection Techniques at 0.2<z<1.2

We present a study of Spitzer/IRAC and X-ray active galactic nuclei (AGNs) selection techniques in order to quantify the overlap, uniqueness, contamination, and completeness of each. We investigate how the overlap and possible contamination of the samples depends on the IR and X-ray depths. We use Spitzer/IRAC imaging, Chandra and XMM X-ray imaging, and PRism MUlti-object Survey (PRIMUS) spectroscopic redshifts to construct galaxy and AGN samples at 0.2<z<1.2 over 8 deg^2. We construct samples over a wide range of IRAC flux limits (SWIRE to GOODS depth) and X-ray flux limits (10 ks to 2 Ms). We compare IR-AGN samples defined using the IRAC color selection of Stern et al. and Donley et al. with X-ray detected AGN samples. For roughly similar depth IR and X-ray surveys, we find that ~75% of IR-AGN are identified as X-ray AGN. This fraction increases to ~90% when comparing against the deepest X-ray data, indicating that only ~10% of IR-selected AGN may be heavily obscured. The IR-AGN selection proposed by Stern et al. suffers from contamination by star-forming galaxies at various redshifts when using deeper IR data, though the selection technique works well for shallow IR data. While similar overall, the IR-AGN samples preferentially contain more luminous AGN, while the X-ray AGN samples preferentially contain lower specific accretion rate AGN, where the host galaxy light dominates at IR wavelengths. The host galaxy populations of the IR and X-ray AGN samples have similar restframe colors and stellar masses; both selections identify AGN in blue, star-forming and red, quiescent galaxies.