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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.

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) has made one square degree, deep, confusion limited maps at three different bands, centered on the Great Observatories Origins Deep Survey South field. By calculating the covariance of these maps with catalogs of 24 µm sources from the Far-Infrared Deep Extragalactic Legacy Survey (FIDEL), we have determined that the total submillimeter intensities are 8.60 ± 0.59, 4.93 ± 0.34, and 2.27 ± 0.20 nW m −2 sr −1 at 250, 350, and 500 µm, respectively. These numbers are more precise than previous estimates of the cosmic infrared background (CIB) and are consistent with 24 µm-selected galaxies generating the full intensity of the CIB. We find that the fraction of the CIB that originates from sources at z ≥ 1.2 increases with wavelength, with 60% from high redshift sources at 500 µm. At all BLAST wavelengths, the relative intensity of high-z sources is higher for 24 µm-faint sources than it is for 24 µm-bright sources. Galaxies identified as active galactic nuclei (AGN) by their Infrared Array Camera (IRAC) colors are 1.6-2.6 times brighter than the average population at 250-500 µm, consistent with what is found for X-ray-selected AGN. BzK-selected galaxies are found to be moderately brighter than typical 24 µmselected galaxies in the BLAST bands. These data provide high precision constraints for models of the evolution of the number density and intensity of star forming galaxies at high redshift.

Submillimetre surveys during the past decade have discovered a population of luminous, high-redshift, dusty starburst galaxies [1][2][3][4][5][6][7][8] . In the redshift range 1 ≤ z ≤ 4, these massive submillimetre galaxies go through a phase characterized by optically obscured star formation at rates several hundred times that in the local Universe.Half of the starlight from this highly energetic process is absorbed and thermally reradiated by clouds of dust at temperatures near 30 K with spectral energy distributions peaking at 100 μm in the rest frame 9 . At 1 ≤ z ≤ 4, the peak is redshifted to wavelengths between 200 and 500 μm. The cumulative effect of these galaxies is to yield extragalactic optical and far-infrared backgrounds with approximately equal energy densities. Since the initial detection of the far-infrared respectively. The depth of the BGS-Deep map was chosen to produce maps that have high signal-to-noise ratios and in which the fluctuations are dominated by pixel-to-pixel fluctuations in signals from galaxies rather than detector noise. The BLAST map ( Fig. 1) overlaps some of the deepest multiwavelength data that exist in a cosmological survey, including radio, infrared, optical (Hubble Ultra Deep Field ) and X-ray (Extended Chandra Deep Field-South) surveys 13,14 . The BGS-Wide map was designed to match the coverage area and sensitivity of the near-infrared and mid-infrared Spitzer Wide-area Infrared Extragalactic survey 15 . By considering both of the data sets together, we derive a catalogue of sources that covers a large dynamic range, (a factor of 50 in flux density)with sufficient sensitivity to resolve the FIRB into individual galaxies. The area is largePage 3 of 12 enough that the source counts are minimally affected by clustering. The BLAST survey contains approximately 500 sources with significant (>5σ) detections.The brightness distribution, or number counts, of submillimetre sources probes the luminosity function in relation to redshift and can be used to constrain models for the formation and evolution of dusty, star-forming galaxies. Models that simultaneously fit the entire range of existing data (24-850 μm) include at least two distinct galaxy populations with different spectral energy distributions and evolutionary histories 16,17 .The BLAST data uniquely bridge these wavelengths across the energetic peak in the FIRB, and provide new strong constraints on the details of the evolution of these populations.The number counts cannot be obtained directly from the distribution of detected sources in the BLAST catalogues because of several well-known biases. (1) Rather than attempting to correct our source list for each of these effects, we estimate the counts from the distribution of pixel brightnesses in the entire map. This P(D) analysis 19 implicitly handles all of the effects mentioned above, yet uses more of the information available to us than just the brightest pixels of the extracted point sources in our catalogues. Figure 2 shows the BLAST number counts with the results f...