We present new arcminute-resolution maps of the Cosmic Microwave Background temperature and polarization anisotropy from the Atacama Cosmology Telescope, using data taken from 2013–2016 at 98 and 150 GHz. The maps cover more than 17,000 deg2, the deepest 600 deg2 with noise levels below 10μK-arcmin. We use the power spectrum derived from almost 6,000 deg2 of these maps to constrain cosmology. The ACT data enable a measurement of the angular scale of features in both the divergence-like polarization and the temperature anisotropy, tracing both the velocity and density at last-scattering. From these one can derive the distance to the last-scattering surface and thus infer the local expansion rate, H 0. By combining ACT data with large-scale information from WMAP we measure H 0=67.6± 1.1 km/s/Mpc, at 68% confidence, in excellent agreement with the independently-measured Planck satellite estimate (from ACT alone we find H 0=67.9± 1.5 km/s/Mpc). The ΛCDM model provides a good fit to the ACT data, and we find no evidence for deviations: both the spatial curvature, and the departure from the standard lensing signal in the spectrum, are zero to within 1σ; the number of relativistic species, the primordial Helium fraction, and the running of the spectral index are consistent with ΛCDM predictions to within 1.5–2.2σ. We compare ACT, WMAP, and Planck at the parameter level and find good consistency; we investigate how the constraints on the correlated spectral index and baryon density parameters readjust when adding CMB large-scale information that ACT does not measure. The DR4 products presented here will be publicly released on the NASA Legacy Archive for Microwave Background Data Analysis.

We present the temperature and polarization angular power spectra of the CMB measured by the Atacama Cosmology Telescope (ACT) from 5400 deg2 of the 2013–2016 survey, which covers >15000 deg2 at 98 and 150 GHz. For this analysis we adopt a blinding strategy to help avoid confirmation bias and, related to this, show numerous checks for systematic error done before unblinding. Using the likelihood for the cosmological analysis we constrain secondary sources of anisotropy and foreground emission, and derive a “CMB-only” spectrum that extends to ℓ=4000. At large angular scales, foreground emission at 150 GHz is ∼1% of TT and EE within our selected regions and consistent with that found by Planck. Using the same likelihood, we obtain the cosmological parameters for ΛCDM for the ACT data alone with a prior on the optical depth of τ=0.065±0.015. ΛCDM is a good fit. The best-fit model has a reduced χ2 of 1.07 (PTE=0.07) with H 0=67.9±1.5 km/s/Mpc. We show that the lensing BB signal is consistent with ΛCDM and limit the celestial EB polarization angle to ψ P  =−0.07̂±0.09̂. We directly cross correlate ACT with Planck and observe generally good agreement but with some discrepancies in TE. All data on which this analysis is based will be publicly released.

A Large Quasar Group (LQG) of particularly large size and high membership has been identified in the DR7QSO catalogue of the Sloan Digital Sky Survey. It has characteristic size (volume 1/3 ) ∼ 500 Mpc (proper size, present epoch), longest dimension ∼ 1240 Mpc, membership of 73 quasars, and mean redshiftz = 1.27. In terms of both size and membership it is the most extreme LQG found in the DR7QSO catalogue for the redshift range 1.0 z 1.8 of our current investigation. Its location on the sky is ∼ 8.8 • north (∼ 615 Mpc projected) of the Clowes & Campusano LQG at the same redshift,z = 1.28, which is itself one of the more extreme examples. Their boundaries approach to within ∼ 2 • (∼ 140 Mpc projected). This new, huge LQG appears to be the largest structure currently known in the early universe. Its size suggests incompatibility with the Yadav et al. scale of homogeneity for the concordance cosmology, and thus challenges the assumption of the cosmological principle.

We use the weak gravitational lensing effect to study the mass distribution and dynamical state of a sample of 24 X-ray luminous clusters of galaxies (0.05 < z < 0.31) observed with the FORS1 instrument mounted on the VLT-Antu (Unit Telescope 1) under homogeneous sky conditions and subarsecond image quality. The galaxy shapes were measured in the combined V, I, R image after deconvolution with a locally determined point-spread-function, while the two-dimensional mass distributions of the clusters were computed using an algorithm based on the maximum entropy method. By comparing the mass and light distributions of the clusters in our sample, we find that their mass centers, for the majority of the clusters, is consistent with the positions of optical centers. We find that some clusters present significant mass substructures which generally have optical counterparts. At least in one cluster (Abell 1451), we detect a mass substructure without an obvious luminous counterpart. The radial profile of the shear of the clusters was fitted using circular and elliptical isothermal elliptical distributions, which allowed the finding of a strong correlation between the orientation of the major-axis of the matter distribution and the corresponding major-axes of the brightest cluster galaxy light-profiles. Estimates of how close to dynamical relaxation are these clusters were obtained through comparison of our weaklensing mass measurements with the x-ray and velocity dispersion determinations available in the literature. We find that clusters with intra-cluster gas colder than 8 keV show a good agreement between the different mass determinations, but clusters with gas hotter than 8 keV present discrepant mass values. The clusters diagnosed to be out of equilibrium are Abell 1451, 2163 and 2744, all of them having hints of substructure. Abell 2744 presents the largest discrepancy between its X-ray and weak-lensing temperature determinations, which can be interpreted as being due to the interaction between the two kinematical components along the line of sight found by Girardi & Mezzeti (2001).

We have obtained I-band Tully-Fisher (T-F) measurements for 522 late-type galaxies in the Ðelds of 52 rich Abell clusters distributed throughout the sky between D50 and 200 h~1 Mpc. Here we estimate corrections to the data for various forms of observational bias, most notably Malmquist and cluster population incompleteness bias. The bias-corrected data are applied to the construction of an I-band T-F template, resulting in a relation with a dispersion of 0.38 mag and a kinematic zero point accurate to 0.02 mag. This represents the most accurate T-F template relation currently available. Individual cluster T-F relations are referred to the average template relation to compute cluster peculiar motions. The line-of-sight dispersion in the peculiar motions is 341^93 km s~1, in general agreement with that found for the cluster sample of Giovanelli and coworkers.