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The lensing effect of the cosmic microwave background (CMB) is a powerful tool for our study of the distribution of matter in the universe. The quadratic estimator (QE) method, which is widely used to reconstruct lensing potential, has been known to be suboptimal for the low noise level polarization data from next-generation CMB experiments. To improve the performance of the reconstruction, other methods, such as the maximum-likelihood estimator and machine-learning algorithms, have been developed. In this work, we present a deep convolutional neural network model named the Residual Dense Local Feature U-net (RDLFUnet) for reconstructing the CMB lensing convergence field. By simulating lensed CMB data with different noise levels to train and test network models, we find that for noise levels less than 5 μ K-arcmin, RDLFUnet can recover the input gravitational potential with a higher signal-to-noise ratio than the previous deep-learning and traditional QE methods at almost the entire observation scale. [ABSTRACT FROM AUTHOR]

We introduce COMAP- EoR, the next generation of the Carbon Monoxide Mapping Array Project aimed at extending CO intensity mapping to the Epoch of Reionization. COMAP- EoR supplements the existing 30 GHz COMAP Pathfinder with two additional 30 GHz instruments and a new 16 GHz receiver. This combination of frequencies will be able to simultaneously map CO(1â€"0) and CO(2â€"1) at reionization redshifts (z ∼ 5â€"8) in addition to providing a significant boost to the z ∼ 3 sensitivity of the Pathfinder. We examine a set of existing models of the EoR CO signal, and find power spectra spanning several orders of magnitude, highlighting our extreme ignorance about this period of cosmic history and the value of the COMAP- EoR measurement. We carry out the most detailed forecast to date of an intensity mapping cross correlation, and find that five out of the six models we consider yield signal to noise ratios (S/Ns) ≳ 20 for COMAP- EoR, with the brightest reaching a S/N above 400. We show that, for these models, COMAP- EoR can make a detailed measurement of the cosmic molecular gas history from z ∼ 2â€"8, as well as probe the population of faint, star-forming galaxies predicted by these models to be undetectable by traditional surveys. We show that, for the single model that does not predict numerous faint emitters, a COMAP- EoR -type measurement is required to rule out their existence. We briefly explore prospects for a third-generation Expanded Reionization Array (COMAP- ERA) capable of detecting the faintest models and characterizing the brightest signals in extreme detail. [ABSTRACT FROM AUTHOR]

The cosmic infrared background (CIB) anisotropies and cosmic microwave background (CMB) lensing are powerful measurements for exploring cosmological and astrophysical problems. In this work, we measure the autocorrelation power spectrum of the CIB anisotropies in the Herschel–SPIRE HerMES Large Mode Survey (HeLMS) field, and the cross-power spectrum with the CMB lensing measurements from the Planck satellite. The HeLMS field covers more than 270 deg2, which is much larger than in previous analysis. We use the Herschel Level 1 time stream data to merge the CIB maps at 250, 350, and 500 μm bands, and mask the areas where the flux is greater than or there are no measured data. We obtain the final CIB power spectra at 100 ≤ ℓ ≤ 20,000 by considering several effects, such as beam function, mode coupling, transfer function, and so on. We also calculate the theoretical CIB auto- and cross-power spectra of CIB and CMB lensing by assuming that the CIB emissivity follows a Gaussian distribution in redshift. We find that, for the CIB auto-power spectra, we obtain signal-to-noise ratios (S/Ns) of 15.9, 15.7, and 15.3 at 250, 350, and 500 μm, and for the CIB ⨯ CMB lensing power spectra, S/Ns of 7.5, 7.0, and 6.2 at 250, 350, and 500 μm, respectively. Comparing to previous works, the constraints on the relevant CIB parameters are improved by factors of 2– 5 in this study. [ABSTRACT FROM AUTHOR]

We consider the cross-correlation between free electrons and neutral hydrogen during the epoch of reionization (EoR). The free electrons are traced by the optical depth to reionization τ, while the neutral hydrogen can be observed through 21 cm photon emission. As expected, this correlation is sensitive to the detailed physics of reionization. Foremost, if reionization occurs through the merger of relatively large halos hosting an ionizing source, the free electrons and neutral hydrogen are anticorrelated for most of the reionization history. A positive contribution to the correlation can occur when the halos that can form an ionizing source are small. A measurement of this sign change in the cross-correlation could help disentangle the bias and the ionization history. We estimate the signal-to-noise ratio of the cross-correlation using the estimator for inhomogeneous reionization proposed by Dvorkin and Smith. We find that with upcoming radio interferometers and cosmic microwave background (CMB) experiments, the cross-correlation is measurable going up to multipoles ℓ ∼ 1000. We also derive parameter constraints and conclude that, despite the foregrounds, the cross-correlation provides a complementary measurement of the EoR parameters to the 21 cm and CMB polarization autocorrelations expected to be observed in the coming decade. [ABSTRACT FROM AUTHOR]

We examine the Sunyaev-Zeldovich (SZ) effect in the seven year Wilkinson Microwave Anisotropy Probe (WMAP) data by cross-correlating it with the Planck Early-release Sunyaev-Zeldovich catalog. Our analysis proceeds in two parts. We first perform a stacking analysis in which the filtered WMAP data are averaged at the locations of the 175 Planck clusters. We then perform a regression analysis to compare the mean amplitude of the SZ signal, Y500, in the WMAP data to the corresponding amplitude in the Planck data. The aggregate Planck clusters are detected in the seven year WMAP data with a signal-to-noise ratio of 16.3. In the regression analysis, we find that the SZ amplitude measurements agree to better than 25%: a = 1.23 ± 0.18 for the fit Y wmap 500 = aY planck 500 . [ABSTRACT FROM AUTHOR]

We report on 23 clusters detected blindly as Sunyaev-Zel'dovich (SZ) decrements in a 148 GHz, 455 deg² map of the southern sky made with data from the Atacama Cosmology Telescope 2008 observing season. All SZ detections announced in this work have confirmed optical counterparts. Ten of the clusters are new discoveries. One newly discovered cluster, ACT-CL J0102-4915, with a redshift of 0.75 (photometric), has an SZ decrement comparable to the most massive systems at lower redshifts. Simulations of the cluster recovery method reproduce the sample purity measured by optical follow-up. In particular, for clusters detected with a signal-to-noise ratio greater than six, simulations are consistent with optical follow-up that demonstrated this subsample is 100% pure. The simulations further imply that the total sample is 80% complete for clusters with mass in excess of 6 x 1014 solar masses referenced to the cluster volume characterized by 500 times the critical density. The Compton y-X-ray luminosity mass comparison for the 11 best-detected clusters visually agrees with both self-similar and non-adiabatic, simulation-derived scaling laws. [ABSTRACT FROM AUTHOR]

We predict the performance of the Planck satellite in determining the bulk flow through kinetic Sunyaev-Zeldovich (kSZ) measurements. As velocity tracers, we use ROSAT All-Sky Survey (RASS) clusters as well as expected cluster catalogs from the upcoming missions Planck and eRosita (All-Sky Survey: EASS). We implement a semi-analytical approach to simulate realistic Planck maps as well as Planck and eRosita cluster catalogs. We adopt an unbiased kSZ filter (UF) and matched filter (MF) to maximize the cluster kSZ signal-to-noise ratio. We find that the use of Planck cosmic microwave background maps in conjunction with the currently existing ROSAT cluster sample improves current upper limits on the bulk flow determination by a factor ~5 (~10) when using the MF (UF). The accuracy of bulk flow measurement increases with the depth and abundance of the cluster sample: for an input bulk velocity of 500 km s ', the UF recovered velocity errors decrease from 94 km s-1 for RASS, to 73 km s-1 for Planck, and to 24 km s-1 for EASS; while the systematic bias decreases from 44% for RASS, 5% for Planck, to 0% for EASS. The 95% upper limit for the recovered bulk flow direction Δα ranges between 4° and 60° depending on cluster sample and adopted filter. The kSZ dipole determination is mainly limited by the effects of thermal SZ emission in all cases but the one of EASS clusters analyzed with the unbiased filter. This fact makes the UF preferable to the MF when analyzing Planck maps. [ABSTRACT FROM AUTHOR]

We expect a detectable correlation between two seemingly unrelated quantities: the four-point function of the cosmic microwave background (CMB) and the amplitude of flux decrements in quasar (QSO) spectra. The amplitude of CMB convergence in a given direction measures the projected surface density of matter. Measurements of QSO flux decrements trace the small-scale distribution of gas along a given line of sight.While the cross-correlation between these two measurements is small for a single line of sight, upcoming large surveys should enable its detection. This paper presents analytical estimates for the signal-to-noise ratio (S/N) for measurements of the cross-correlation between the flux decrement and the convergence, (δFκ), and for measurements of the cross-correlation between the variance in flux decrement and the convergence, ((δF)²κ). For the ongoing BOSS (SDSS-III) and Planck surveys, we estimate an S/N of 30 and 9.6 for these two correlations. For the proposed BigBOSS and ACTPOL surveys, we estimate an S/N of 130 and 50, respectively. Since ((δF)²κ) ∝ σ84, the amplitude of these cross-correlations can potentially be used to measure the amplitude of σ8 at z ∼ 2%-2.5% with BOSS and Planck and even better with future data sets. These measurements have the potential to test alternative theories for dark energy and to constrain the mass of the neutrino. The large potential signal estimated in our analytical calculations motivates tests with nonlinear hydrodynamic simulations and analyses of upcoming data sets. [ABSTRACT FROM AUTHOR]

We present cosmological constraints based on the cosmic microwave background (CMB) lensing potential power spectrum measurement from the recent 500 deg2 SPTpol survey, the most precise CMB lensing measurement from the ground to date. We fit a flat ΛCDM model to the reconstructed lensing power spectrum alone and in addition with other data sets: baryon acoustic oscillations (BAO), as well as primary CMB spectra from Planck and SPTpol. The cosmological constraints based on SPTpol and Planck lensing band powers are in good agreement when analyzed alone and in combination with Planck full-sky primary CMB data. With weak priors on the baryon density and other parameters, the SPTpol CMB lensing data alone provide a 4% constraint on . Jointly fitting with BAO data, we find , , and , up to away from the central values preferred by Planck lensing + BAO. However, we recover good agreement between SPTpol and Planck when restricting the analysis to similar scales. We also consider single-parameter extensions to the flat ΛCDM model. The SPTpol lensing spectrum constrains the spatial curvature to be and the sum of the neutrino masses to be eV at 95% C.L. (with Planck primary CMB and BAO data), in good agreement with the Planck lensing results. With the differences in the signal-to-noise ratio of the lensing modes and the angular scales covered in the lensing spectra, this analysis represents an important independent check on the full-sky Planck lensing measurement. [ABSTRACT FROM AUTHOR]

We perform forecasts for how baryon acoustic oscillation (BAO) scale and redshift-space distortion (RSD) measurements from future spectroscopic emission line galaxy surveys such as Euclid are degraded in the presence of spectral line misidentification. Using analytic calculations verified with mock galaxy catalogs from lognormal simulations, we find that constraints are degraded in two ways, even when the interloper power spectrum is modeled correctly in the likelihood. First, there is a loss of signal-to-noise ratio for the power spectrum of the target galaxies, which propagates to all cosmological constraints and increases with contamination fraction, fc. Second, degeneracies can open up between fc and cosmological parameters. In our calculations, this typically increases BAO scale uncertainties at the 10%–20% level when marginalizing over parameters determining the broadband power spectrum shape. External constraints on fc or parameters determining the shape of the power spectrum, for example, from cosmic microwave background measurements, can remove this effect. There is a near-perfect degeneracy between fc and the power spectrum amplitude for low fc values, where fc is not well determined from the contaminated sample alone. This has the potential to strongly degrade RSD constraints. The degeneracy can be broken with an external constraint on fc, for example, from cross-correlation with a separate galaxy sample containing the misidentified line or deeper subsurveys. [ABSTRACT FROM AUTHOR]

We present weak-lensing measurements using the first-year data from the Hyper Suprime-Cam Strategic Survey Program on the Subaru telescope for eight galaxy clusters selected through their thermal Sunyaev–Zel’dovich (SZ) signal measured at 148 GHz with the Atacama Cosmology Telescope Polarimeter experiment. The overlap between the two surveys in this work is 33.8 square degrees, before masking bright stars. The signal-to-noise ratio of individual cluster lensing measurements ranges from 2.2 to 8.7, with a total of 11.1 for the stacked cluster weak-lensing signal. We fit for an average weak-lensing mass distribution using three different profiles, a Navarro–Frenk–White profile, a dark-matter-only emulated profile, and a full cosmological hydrodynamic emulated profile. We interpret the differences among the masses inferred by these models as a systematic error of 10%, which is currently smaller than the statistical error. We obtain the ratio of the SZ-estimated mass to the lensing-estimated mass (the so-called hydrostatic mass bias 1−b) of , which is comparable to previous SZ-selected clusters from the Atacama Cosmology Telescope and from the Planck Satellite. We conclude with a discussion of the implications for cosmological parameters inferred from cluster abundances compared to cosmic microwave background primary anisotropy measurements. [ABSTRACT FROM AUTHOR]

We present measurements of the E-mode polarization angular auto-power spectrum (EE) and temperature–E-mode cross-power spectrum (TE) of the cosmic microwave background (CMB) using 150 GHz data from three seasons of SPTpol observations. We report the power spectra over the spherical harmonic multipole range and detect nine acoustic peaks in the EE spectrum with high signal-to-noise ratio. These measurements are the most sensitive to date of the EE and TE power spectra at and , respectively. The observations cover 500 , a fivefold increase in area compared to previous SPTpol analyses, which increases our sensitivity to the photon diffusion damping tail of the CMB power spectra enabling tighter constraints on ΛCDM model extensions. After masking all sources with unpolarized flux mJy, we place a 95% confidence upper limit on residual polarized point-source power of at , suggesting that the EE damping tail dominates foregrounds to at least with modest source masking. We find that the SPTpol data set is in mild tension with the ΛCDM model (), and different data splits prefer parameter values that differ at the level. When fitting SPTpol data at , we find cosmological parameter constraints consistent with those for Planck temperature. Including SPTpol data at results in a preference for a higher value of the expansion rate ( ) and a lower value for present-day density fluctuations (). [ABSTRACT FROM AUTHOR]

The extragalactic γ-ray background and its spatial anisotropy could potentially contain a signature of dark matter (DM) annihilation or particle decay. Astrophysical foregrounds, such as blazars and star-forming galaxies (SFGs), however, dominate the γ-ray background, precluding an easy detection of the signal associated with the DM annihilation or decay in the background intensity spectrum. The DM imprint on the γ-ray background is expected to be correlated with large-scale structure tracers. In some cases, such a cross-correlation is even expected to have a higher signal-to-noise ratio than the auto-correlation. One reliable tracer of the DM distribution in the large-scale structure is lensing of the cosmic microwave background (CMB), and the cosmic infrared background (CIB) is a reliable tracer of SFGs. We analyze Fermi-LAT data taken over 92 months and study the cross-correlation with Planck CMB lensing, Planck CIB, and Fermi-γ maps. We put upper limits on the DM annihilation cross-section from the cross-power spectra with the γ-ray background anisotropies. The unbiased power spectrum estimation is validated with simulations that include cross-correlated signals. We also provide a set of systematic tests and show that no significant contaminations are found for the measurements presented here. Using γ-ray background map from data gathered over 92 months, we find the best constraint on the DM annihilation with a confidence level upper limit of 10−25–10−24 cm3 s−1, when the mass of DM particles is between 20 and 100 GeV. [ABSTRACT FROM AUTHOR]

We present an improved and extended analysis of the cross-correlation between the map of the cosmic microwave background (CMB) lensing potential derived from the Planck mission data and the high-redshift galaxies detected by the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) in the photometric redshift range . We compare the results based on the 2013 and 2015 Planck datasets, and investigate the impact of different selections of the H-ATLAS galaxy samples. Significant improvements over our previous analysis have been achieved thanks to the higher signal-to-noise ratio of the new CMB lensing map recently released by the Planck collaboration. The effective galaxy bias parameter, b, for the full galaxy sample, derived from a joint analysis of the cross-power spectrum and of the galaxy auto-power spectrum is found to be . Furthermore, a first tomographic analysis of the cross-correlation signal is implemented by splitting the galaxy sample into two redshift intervals: and . A statistically significant signal was found for both bins, indicating a substantial increase with redshift of the bias parameter: for the lower and for the higher redshift bin. Consistent with our previous analysis, we find that the amplitude of the cross-correlation signal is a factor of higher than expected from the standard ΛCDM model for the assumed redshift distribution. The robustness of our results against possible systematic effects has been extensively discussed, although the tension is mitigated by passing from 4 to 3σ. [ABSTRACT FROM AUTHOR]

Photons emitted during cosmological hydrogen () and helium recombination ( for He ii He i, for He iii He ii) are predicted to appear as broad, weak spectral distortions of the cosmic microwave background. We present a feasibility study for a ground-based detection of these recombination lines, which would uniquely probe astrophysical cosmology beyond the last scattering surface and provide observational constraints on the thermal history of the universe. We find that including sufficient signal spectral structure and maximizing signal-to-noise ratio, an octave band in the 2–6 GHz window is optimal; in this band the predicted signal appears as an additive quasi-sinusoidal component with amplitude about 8 nK embedded in a sky spectrum some nine orders of magnitude brighter. We discuss algorithms to detect these tiny spectral fluctuations in the sky spectrum by foreground modeling and introduce a maximally smooth function capable of describing the foreground spectrum and distinguishing the signal of interest. We conclude that detection is in principle feasible in realistic observing times provided that radio frequency interference and instrument bandpass calibration are controlled in this band at the required level; using Bayesian tests and mock data, we show that 90% confidence detection is possible with an array of 128 radiometers observing for 255 days of effective integration time. We propose APSERa—Array of Precision Spectrometers for the Epoch of Recombination—a dedicated radio telescope to detect these recombination lines. [ABSTRACT FROM AUTHOR]

We present a method to test the isotropy of the magnitude–redshift relation of Type Ia Supernovae (SNe Ia) and single out the most discrepant direction (in terms of the signal-to-noise ratio) with respect to the all-sky data. Our technique accounts for possible directional variations of the corrections for SNe Ia and yields all-sky maps of the best-fit cosmological parameters with arbitrary angular resolution. To show its potential, we apply our method to the high-redshift SNe Ia from the recent Union2.1 compilation, building maps with three different angular resolutions. We use a Monte Carlo method to estimate the statistical significance with which we could reject the null hypothesis that the magnitude–redshift relation is isotropic based on the properties of the observed most discrepant directions. We find that, based on pure signal-to-noise arguments, the null hypothesis cannot be rejected at any meaningful confidence level. However, if we also consider that the strongest deviations in the Union2.1 sample closely align with the dipole temperature anisotropy of the cosmic microwave background, we find that the null hypothesis should be rejected at the 95%–99% confidence level, slightly depending on the angular resolution of the study. If this result is not due to a statistical fluke, it might either indicate that the SN data have not been cleaned from all possible systematics or even point toward new physics. We finally discuss future perspectives in the field for achieving larger and more uniform data sets that will vastly improve the quality of the results and optimally exploit our method. [ABSTRACT FROM AUTHOR]

We present a measurement of the cosmic microwave background (CMB) gravitational lensing potential using data from the first two seasons of observations with SPTpol, the polarization-sensitive receiver currently installed on the South Pole Telescope. The observations used in this work cover 100 deg2 of sky with arcminute resolution at 150 GHz. Using a quadratic estimator, we make maps of the CMB lensing potential from combinations of CMB temperature and polarization maps. We combine these lensing potential maps to form a minimum-variance (MV) map. The lensing potential is measured with a signal-to-noise ratio of greater than one for angular multipoles between . This is the highest signal-to-noise mass map made from the CMB to date and will be powerful in cross-correlation with other tracers of large-scale structure. We calculate the power spectrum of the lensing potential for each estimator, and we report the value of the MV power spectrum between as our primary result. We constrain the ratio of the spectrum to a fiducial ΛCDM model to be AMV = 0.92 ± 0.14 (Stat.) ± 0.08 (Sys.). Restricting ourselves to polarized data only, we find APOL = 0.92 ± 0.24 (Stat.) ± 0.11 (Sys.). This measurement rejects the hypothesis of no lensing at using polarization data alone, and at using both temperature and polarization data. [ABSTRACT FROM AUTHOR]