On the recovery of ISW fluctuations using large-scale structure tracers and CMB temperature and polarization anisotropies

In this work we present a method to extract the signal induced by the integrated Sachs-Wolfe (ISW) effect in the cosmic microwave background (CMB). It makes use of the Linear Covariance-Based filter introduced by Barreiro et al., and combines CMB data with any number of large-scale structure (LSS) surveys and lensing information. It also exploits CMB polarization to reduce cosmic variance. The performance of the method has been thoroughly tested with simulations taking into account the impact of non-ideal conditions such as incomplete sky coverage or the presence of noise. In particular, three galaxy surveys are simulated, whose redshift distributions peak at low ($z \simeq 0.3$), intermediate ($z \simeq 0.6$) and high redshift ($z \simeq 0.9$). The contribution of each of the considered data sets as well as the effect of a mask and noise in the reconstructed ISW map is studied in detail. When combining all the considered data sets (CMB temperature and polarization, the three galaxy surveys and the lensing map), the proposed filter successfully reconstructs a map of the weak ISW signal, finding a perfect correlation with the input signal for the ideal case and around 80 per cent, on average, in the presence of noise and incomplete sky coverage. We find that including CMB polarization improves the correlation between input and reconstruction although only at a small level. Nonetheless, given the weakness of the ISW signal, even modest improvements can be of importance. In particular, in realistic situations, in which less information is available from the LSS tracers, the effect of including polarisation is larger. For instance, for the case in which the ISW signal is recovered from CMB plus only one survey, and taking into account the presence of noise and incomplete sky coverage, the improvement in the correlation coefficient can be as large as 10 per cent.Comment: 17 pages, 15 figures, accepted for publication in MNRA

Statistics of the fractional polarisation of compact radio sources in Planck maps

In this work we apply the stacking technique to estimate the average fractional polarisation from 30 to 353 GHz of a primary sample of 1560 compact sources - essentially all radio sources - detected in the 30 GHz Planck all-sky map and listed in the second version of the Planck Catalogue of Compact Sources (PCCS2). We divide our primary sample in two subsamples according to whether the sources lay (679 sources) or not (881 sources) inside the sky region defined by the Planck Galactic mask (fsky ~ 60 per cent) and the area around the Magellanic Clouds. We find that the average fractional polarisation of compact sources is approximately constant (with frequency) in both samples (with a weighted mean over all the channels of 3.08 per cent outside and 3.54 per cent inside the Planck mask). In the sky region outside the adopted mask, we also estimate the {\mu} and {\sigma} parameters for the log-normal distribution of the fractional polarisation, finding a weighted mean value over all the Planck frequency range of 1.0 for {\sigma} and 0.7 for {\mu} (that would imply a weighted mean value for the median fractional polarisation of 1.9 per cent).Comment: 12 pages, 7 figures, 2 tables, MNRAS in pres

Statistics of the fractional polarisation of extragalactic dusty sources in Planck HFI maps

We estimate the average fractional polarisation at 143, 217 and 353 GHz of a sample of 4697 extragalactic dusty sources by applying stacking technique. The sample is selected from the second version of the Planck Catalogue of Compact Sources at 857 GHz, avoiding the region inside the Planck Galactic mask (fsky ~ 60 per cent). We recover values for the mean fractional polarisation at 217 and 353 GHz of (3.10 \pm 0.75) per cent and (3.65 \pm 0.66) per cent, respectively, whereas at 143 GHz we give a tentative value of (3.52 \pm 2.48) per cent. We discuss the possible origin of the measured polarisation, comparing our new estimates with those previously obtained from a sample of radio sources. We test different distribution functions and we conclude that the fractional polarisation of dusty sources is well described by a log-normal distribution, as determined in the radio band studies. For this distribution we estimate {\mu}_{217GHz} = 0.3 \pm 0.5 (that would correspond to a median fractional polarisation of {\Pi}_{med} = (1.3 \pm 0.7) per cent) and {\mu}_{353GHz} = 0.7 \pm 0.4 ({\Pi}_{med} = (2.0 \pm 0.8) per cent), {\sigma}_{217GHz} = 1.3 \pm 0.2 and {\sigma}_{353GHz} = 1.1 \pm 0.2. With these values we estimate the source number counts in polarisation and the contribution given by these sources to the CMB B-mode angular power spectrum at 217, 353, 600 and 800 GHz. We conclude that extragalactic dusty sources might be an important contaminant for the primordial B-mode at frequencies > 217 GHz.Comment: arXiv admin note: text overlap with arXiv:1703.0995

The Planck-ATCA Co-eval Observations (PACO) project: the bright sample

The Planck-ATCA Co-eval Observations (PACO) have provided flux density measurements of well defined samples of AT20G radio sources at frequencies below and overlapping with Planck frequency bands, almost simultaneously with Planck observations. We have observed with the Australia Telescope Compact Array (ATCA) a total of 482 sources in the frequency range between 4.5 and 40 GHz in the period between July 2009 and August 2010. Several sources were observed more than once. In this paper we present the aims of the project, the selection criteria, and the observation and data reduction procedures. We also discuss the data in total intensity for a complete sample of 189 sources with S(20 GHz)>500 mJy, Galactic latitude |b|>5deg, and declination <-30deg, and some statistical analysis of the spectral behaviour and variability of this sample, referred to as the "bright PACO sample". Finally we discuss how these data could be used to transfer absolute calibrations to ground based telescopes using the CMB dipole calibrated flux densities measured by the Planck satellite, and we provide some test fluxes on bright calibrators.Comment: 15 pages, 11 figure. Accepted for publication on MNRAS. Catalogue availabl

The Planck-ATCA Co-eval Observations (PACO) project: analysis of radio source properties between 5 and 217 GHz

The Planck-ATCA Co-eval Observations (PACO) project has yielded observations of 464 sources with the Australia Telescope Compact Array (ATCA) between 4.5 and 40 GHz. The main purpose of the project was to investigate the spectral properties of mm-selected radio sources at frequencies below and overlapping with the ESA's Planck satellite frequency bands, minimizing the variability effects by observing almost simultaneously with the first two Planck all-sky surveys. In this paper we present the whole catalogue of observations in total intensity. By comparing PACO with the various measures of Planck Catalog of Compact Sources (PCCS) flux densities we found the best consistency with the PCCS "detection pipeline" photometry (DETFLUX) that we used to investigate the spectral properties of sources from 5 to 217 GHz. Of our sources, 91% have remarkably smooth spectrum, well described by a double power law over the full range. This suggests a single emitting region, at variance with the notion that "flat" spectra result from the superposition of the emissions from different compact regions, self absorbed up to different frequencies. Most of the objects show a spectral steepening above 30 GHz, consistent with synchrotron emission becoming optically thin. Thus, the classical dichotomy between flat-spectrum/compact and steep-spectrum/extended radio sources, well established at cm wavelengths, breaks down at mm wavelengths. The mm-wave spectra do not show indications of the spectral break expected as the effect of "electron ageing", suggesting young source ages.Comment: 15 pages, 7 figures, accepted for publication in MNRA

A direct and robust method to observationally constrain the halo mass function via the submillimeter magnification bias: Proof of concept

Aims. The main purpose of this work is to provide a proof-of-concept method to derive tabulated observational constraints on the halo mass function (HMF) by studying the magnification bias effect on high-redshift submillimeter galaxies. Under the assumption of universality, we parametrize the HMF according to two traditional models, namely the Sheth and Tormen (ST) and Tinker fits, derive posterior distributions for their parameters, and assess their performance in explaining the measured data within the \u39b cold dark matter model. We also study the potential influence of the halo occupation distribution (HOD) parameters in this analysis and discuss two aspects regarding the HMF parametrization, namely its normalization and the possibility of allowing negative values for the parameters. Methods. We measure the cross-correlation function between a foreground sample of GAMA galaxies with spectroscopic redshifts in the range 0.2 &lt; z &lt; 0.8 and a background sample of H-ATLAS galaxies with photometric redshifts in the range 1.2 &lt; z &lt; 4.0 and carry out a Markov chain Monte Carlo algorithm in the context of Bayesian inference to check this observable against its mathematical prediction within the halo model formalism, which depends on both the HOD and HMF parameters. Results. Under the assumption that all HMF parameters are positive, the ST fit only seems to fully explain the measurements by forcing the mean number of satellite galaxies in a halo to increase substantially from its prior mean value. The Tinker fit, on the other hand, provides a robust description of the data without relevant changes in the HOD parameters, but with some dependence on the prior range of two of its parameters. When the normalization condition for the HMF is dropped and we allow negative values of the p1 parameter in the ST fit, all the involved parameters are better determined, unlike the previous models, thus deriving the most general HMF constraints. While all the aforementioned cases are in agreement with the traditional fits within the uncertainties, the last one hints at a slightly higher number of halos at intermediate and high masses, raising the important point of the allowed parameter range

Early evolution of galaxies and of large-scale structure from CMB experiments

Next generation CMB experiments with arcmin resolution will, for free, lay the foundations for a real breakthrough on the study of the early evolution of galaxies and galaxy clusters, thanks to the detection of large samples of strongly gravitationally lensed galaxies and of proto-clusters of dusty galaxies up to high redshifts. This has an enormous legacy value. High resolution follow-up of strongly lensed galaxies will allow the direct investigation of their structure and kinematics up to z~6, providing direct information on physical processes driving their evolution. Follow-up of proto-clusters will allow an observational validation of the formation history of the most massive dark matter halos up to z~4, well beyond the redshift range accessible via X-ray or SZ measurements. These experiments will also allow a giant leap forward in the determination of polarization properties of extragalactic sources, and will provide a complete census of cold dust available for star formation in the local universe.Comment: Science white paper submitted to the Astro2020 US Decadal Surve