Planck2015 results

Abstract

We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest systematic all-sky survey of galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data sets, and is the first SZ-selected cluster survey containing >10 3 confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the estimates of the SZ strength parameter Y 5R500 are robust to pressureprofile variation and beam systematics, but accurate conversion to Y 500 requires the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical, and X-ray data sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under-luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples.

Extragalactic Astrophysics With Next-Generation CMB Experiments

“…Classical systematic cluster searches were carried out via X-ray [e.g., refs. 77, 78], Sunyaev-Zeldovich [SZ; 79,80,81,82] and optical/near-infrared [83,84,85,86] surveys. These surveys, however, have yielded only a handful of confirmed proto-cluster detections at z ∼ > 1.5 [76].…”

Cosmological constraints from Planck galaxy clusters with CMB lensing mass bias calibration

“…In particular, their abundance as a function of mass and redshift is very sensitive to the mean matter density of the Universe, which can be parametrised by Ω m , and to the amplitude of the matter perturbations, which can be characterised by σ 8 , the root mean square of the linear density fluctuations smoothed on a scale of 8 h −1 Mpc. In recent years, large Sunyaev-Zel'dovich (SZ) cluster surveys, in which clusters are detected through their thermal-SZ (tSZ) signature (Sunyaev & Zeldovich 1972), have provided useful observations of this abundance from which cosmological constraints have been obtained (e.g., Staniszewski et al 2009;Mantz et al 2010;Hasselfield et al 2013;Bleem et al 2015;Planck 2015Results XXVII 2016de Haan et al 2016;Bocquet et al 2019;Salvati et al 2018). SZ surveys are particu-E-mail: inigo.zubeldia@ast.cam.ac.uk † E-mail: a.d.challinor@ast.cam.ac.uk larly interesting because the change in surface brightness of the cosmic microwave background (CMB) due to the SZ effect does not decrease with cluster redshift, allowing for the detection of high-redshift galaxy clusters given enough resolution.…”

“…However, the scaling relations between a cluster's mass and its SZ signal are not very well determined, and usually they need to be calibrated for each survey. This determination of cluster masses currently provides the largest source of uncertainty when obtaining cosmological information from galaxy clusters (Planck 2015Results XXIV 2016Pratt et al 2019).…”

“…Zubeldia et al 2016). A subsample of 439 such clusters, known as the MMF3 cosmology sample, was used in a counts analysis in order to constrain, amongst other parameters and models, Ω m and σ 8 within the context of a standard spatially-flat ΛCDM cosmology (Planck 2015Results XXIV 2016. This analysis proceeded as follows.…”

A new probe of axion-like particles: CMB polarization distortions due to cluster magnetic fields

“…Several CMB experiments have explored the spatially varying part of the blackbody and non-blackbody (particularly y-distortions) over the last three decades from space, balloon -1 -and ground platforms 1 . Along with the unprecedented measurement of the temperature and polarization anisotropy by WMAP [25] and Planck [26], ground-based experiments such as ACT (Atacama Cosmology Telescope) [27] and SPT (South-Pole Telescope) [28] have also explored the y-distortion signals from galaxy clusters [8,[29][30][31][32][33][34]. However, the spatially nonvarying spectrum of the CMB has not been explored after COBE-FIRAS (Cosmic Background Explorer-Far Infrared Absolute Spectrophotometer) experiment [35][36][37][38] which had imposed an upper bound on y-distortions and µ-distortions of 15 × 10 −6 and 9 × 10 −5 respectively at 95% C.L.…”