[en] We measure the average deflection of cosmic microwave background photons by quasars at $⟨<!--\; ???\; -->z⟩<!--\; ???\; -->=1.7$. Our sample is selected from the Sloan Digital Sky Survey to cover the redshift range 0.9 ≤ z ≤ 2.2 with absolute i-band magnitudes of M _i ≤ –24 (K-corrected to z = 2). A stack of nearly 200,000 targets reveals an 8σ detection of Planck's estimate of the lensing convergence toward the quasars. We fit the signal with a model comprising a Navarro–Frenk–White density profile and a two-halo term accounting for correlated large-scale structure, which dominates the observed signal. The best-fitting model is described by an average halo mass ${\mathrm{l}\mathrm{o}\mathrm{g}}_{10}(M_{\mathrm{h}}/h^{-<!--\; ???\; -->1}{M}_{\odot <!--\; ???\; -->})=12.6\pm <!--\; ??\; -->0.2$ and linear bias b = 2.7 ± 0.3 at $⟨<!--\; ???\; -->z⟩<!--\; ???\; -->=1.7$, in excellent agreement with clustering studies. Here, we also report a hint, at a 90% confidence level, of a correlation between the convergence amplitude and luminosity, indicating that quasars brighter than M _i lesssim –26 reside in halos of typical mass $M_{\mathrm{h}}\approx <!--\; ???\; -->{10}^{13}{h}^{-<!--\; ???\; -->1}{M}_{\odot <!--\; ???\; -->}$, scaling roughly as $M_{\mathrm{h}}\propto <!--\; ???\; -->L_{\mathrm{o}\mathrm{p}\mathrm{t}}^{3/4}$ at $M_i\lesssim <!--\; ???\; -->-<!--\; ???\; -->24$ mag, in good agreement with physically motivated quasar demography models. Although we acknowledge that this luminosity dependence is a marginal result, the observed M _h–L _opt relationship could be interpreted as a reflection of the cutoff in the distribution of black hole accretion rates toward high Eddington ratios: the weak trend of M _h with L _opt observed at low luminosity becomes stronger for the most powerful quasars, which tend to be accreting close to the Eddington limit.

[en] We present a study of the redshift evolution of the projected correlation function of 593 X-ray selected active galactic nuclei (AGNs) with I_AB < 23 and spectroscopic redshifts z < 4, extracted from the 0.5-2 keV X-ray mosaic of the 2.13 deg² XMM- Cosmic Evolution Survey (COSMOS). We introduce a method to estimate the average bias of the AGN sample and the mass of AGN hosting halos, solving the sample variance using the halo model and taking into account the growth of the structure over time. We find evidence of a redshift evolution of the bias factor for the total population of XMM-COSMOS AGNs from b-bar ( z-bar =0.92)=2.30±0.11 to b-bar ( z-bar =1.94)=4.37±0.27 with an average mass of the hosting dark matter (DM) halos log M₀(h^-1 M_sun) ∼ 13.12 ± 0.12 that remains constant at all z < 2. Splitting our sample into broad optical line AGNs (BL), AGNs without broad optical lines (NL), and X-ray unobscured and obscured AGNs, we observe an increase of the bias with redshift in the range z-bar = 0.7-2.25 and z-bar = 0.6-1.5 which corresponds to a constant halo mass of log M₀(h^-1 M_sun) ∼ 13.28 ± 0.07 and log M₀(h^-1 M_sun) ∼ 13.00 ± 0.06 for BL/X-ray unobscured AGNs and NL/X-ray obscured AGNs, respectively. The theoretical models, which assume a quasar phase triggered by major mergers, cannot reproduce the high bias factors and DM halo masses found for X-ray selected BL AGNs with L_BOL ∼ 2 x 10⁴⁵ erg s^-1. Our work extends up to z ∼ 2.2 the z ∼< 1 statement that, for moderate-luminosity X-ray selected BL AGNs, the contribution from major mergers is outnumbered by other processes, possibly secular ones such as tidal disruptions or disk instabilities.

[en] We present an analysis of the mid-infrared Wide-field Infrared Survey Explorer (WISE) sources seen within the equatorial GAMA G12 field, located in the North Galactic Cap. Our motivation is to study and characterize the behavior of WISE source populations in anticipation of the deep multiwavelength surveys that will define the next decade, with the principal science goal of mapping the 3D large-scale structures and determining the global physical attributes of the host galaxies. In combination with cosmological redshifts, we identify galaxies from their WISE W1 (3.4 μm) resolved emission, and we also perform a star-galaxy separation using apparent magnitude, colors, and statistical modeling of star counts. The resulting galaxy catalog has ≃590,000 sources in 60 deg², reaching a W1 5σ depth of 31 μJy. At the faint end, where redshifts are not available, we employ a luminosity function analysis to show that approximately 27% of all WISE extragalactic sources to a limit of 17.5 mag (31 μJy) are at high redshift, $z><!--\; >\; -->1$. The spatial distribution is investigated using two-point correlation functions and a 3D source density characterization at 5 Mpc and 20 Mpc scales. For angular distributions, we find that brighter and more massive sources are strongly clustered relative to fainter sources with lower mass; likewise, based on WISE colors, spheroidal galaxies have the strongest clustering, while late-type disk galaxies have the lowest clustering amplitudes. In three dimensions, we find a number of distinct groupings, often bridged by filaments and superstructures. Using special visualization tools, we map these structures, exploring how clustering may play a role with stellar mass and galaxy type.

[en] The Galaxy And Mass Assembly (GAMA) survey furnishes a deep redshift catalog that, when combined with the Wide-field Infrared Survey Explorer (WISE), allows us to explore for the first time the mid-infrared properties of >110, 000 galaxies over 120 deg² to z ≅ 0.5. In this paper we detail the procedure for producing the matched GAMA-WISE catalog for the G12 and G15 fields, in particular characterizing and measuring resolved sources; the complete catalogs for all three GAMA equatorial fields will be made available through the GAMA public releases. The wealth of multiwavelength photometry and optical spectroscopy allows us to explore empirical relations between optically determined stellar mass (derived from synthetic stellar population models) and 3.4 μm and 4.6 μm WISE measurements. Similarly dust-corrected Hα-derived star formation rates can be compared to 12 μm and 22 μm luminosities to quantify correlations that can be applied to large samples to z < 0.5. To illustrate the applications of these relations, we use the 12 μm star formation prescription to investigate the behavior of specific star formation within the GAMA-WISE sample and underscore the ability of WISE to detect star-forming systems at z ∼ 0.5. Within galaxy groups (determined by a sophisticated friends-of-friends scheme), results suggest that galaxies with a neighbor within 100 h ^–1 kpc have, on average, lower specific star formation rates than typical GAMA galaxies with the same stellar mass.