We present a method based on matched multifrequency filters for extracting cluster catalogs from Sunyaev-Zel'dovich (SZ) surveys. We evaluate its performance in terms of completeness, contamination ...rate and photometric recovery for three representative types of SZ survey: a high resolution single frequency radio survey (AMI), a high resolution ground-based multiband survey (SPT), and the Planck all-sky survey. These surveys are not purely flux limited, and they loose completeness significantly before their point-source detection thresholds. Contamination remains relatively low at <5% (less than 30%) for a detection threshold set at $S/N=5$ ($S/N=3$). We identify photometric recovery as an important source of catalog uncertainty: dispersion in recovered flux from multiband surveys is larger than the intrinsic scatter in the $Y-M$ relation predicted from hydrodynamical simulations, while photometry in the single frequency survey is seriously compromised by confusion with primary cosmic microwave background anisotropy. The latter effect implies that follow-up observations in other wavebands (e.g., 90 GHz, X-ray) of single frequency surveys will be required. Cluster morphology can cause a bias in the recovered $Y-M$ relation, but has little effect on the scatter; the bias would be removed during calibration of the relation. Point source confusion only slightly decreases multiband survey completeness; single frequency survey completeness could be significantly reduced by radio point source confusion, but this remains highly uncertain because we do not know the radio counts at the relevant flux levels.
We present the compilation and properties of a meta-catalogue of X-ray detected clusters of galaxies, the MCXC. This very large catalogue is based on publicly available ROSAT All Sky Survey-based ...(NORAS, REFLEX, BCS, SGP, NEP, MACS, and CIZA) and serendipitous (160SD, 400SD, SHARC, WARPS, and EMSS) cluster catalogues. Data have been systematically homogenised to an overdensity of 500, and duplicate entries from overlaps between the survey areas of the individual input catalogues are carefully handled. The MCXC comprises 1743 clusters with virtually no duplicate entries. For each cluster the MCXC provides three identifiers, a redshift, coordinates, membership in the original catalogue, and standardised 0.1−2.4 keV band luminosity L500, total mass M500, and radius R500. The meta-catalogue additionally furnishes information on overlaps between the input catalogues and the luminosity ratios when measurements from different surveys are available, and gives notes on individual objects. The MCXC is available in electronic format for maximum usefulness in X-ray, SZ, and other multiwavelength studies.
We measured the average Compton profile of 461 clusters detected jointly by the South Pole Telescope (SPT) and
Planck
. The number of clusters included in this analysis is about one order of ...magnitude larger than in previous analyses. We propose an innovative method developed in Fourier space to combine optimally the
Planck
and SPT-SZ data, allowing us to perform a clean deconvolution of the point spread and transfer functions while simultaneously rescaling by the characteristic radial scale
R
500
with respect to the critical density. The method additionally corrects for the selection bias of SPT clusters in the SPT-SZ data. We undertake a generalised Navarro–Frenk–White (gNFW) fit to the profile with only one parameter fixed, allowing us to constrain the other four parameters with excellent precision. The best-fitting profile is in good agreement with the universal pressure profile based on REXCESS in the inner region and with the Planck intermediate Paper V profile based on
Planck
and the
XMM-Newton
archive in the outer region. We investigate trends with redshift and mass, finding no indication of redshift evolution but detecting a significant difference in the pressure profile of the low- versus high-mass subsamples, in the sense that the low mass subsample has a profile that is more centrally peaked than that of the high mass subsample. We also scaled the average Compton profile by the mean Universe density (
R
200m
) and provide the best-fitting gNFW profile. Using the profiles scaled by both the critical (
R
500
) and the mean Universe density (
R
200m
), we studied the outskirt regions by reconstructing the average Compton parameter profile in real space. These profiles show multiple pressure drops at
θ
> 2
θ
500
, but these cannot clearly be identified with the accretion shocks predicted by hydrodynamical simulations. This is most probably due to our having reached the noise floor in the outer parts of the average profile with the current data sets.
The XXL Survey Pacaud, F.; Pierre, M.; Melin, J.-B. ...
Astronomy and astrophysics (Berlin),
12/2018, Letnik:
620
Journal Article
Recenzirano
Odprti dostop
Context.
We present an estimation of cosmological parameters with clusters of galaxies.
Aims.
We constrain the Ω
m
,
σ
8
, and
w
parameters from a stand-alone sample of X-ray clusters detected in the ...50 deg
2
XMM-XXL survey with a well-defined selection function.
Methods.
We analyse the redshift distribution of a sample comprising 178 high signal-to-noise ratio clusters out to a redshift of unity. The cluster sample scaling relations are determined in a self-consistent manner.
Results.
In a lambda cold dark matter (ΛCDM) model, the cosmology favoured by the XXL clusters compares well with results derived from the
Planck
Sunyaev-Zel’dovich clusters for a totally different sample (mass/redshift range, selection biases, and scaling relations). However, with this preliminary sample and current mass calibration uncertainty, we find no inconsistency with the
Planck
CMB cosmology. If we relax the
w
parameter, the
Planck
CMB uncertainties increase by a factor of ~10 and become comparable with those from XXL clusters. Combining the two probes allows us to put constraints on Ω
m
= 0.316 ± 0.060,
σ
8
= 0.814 ± 0.054, and
w
= −1.02 ± 0.20.
Conclusions.
This first self-consistent cosmological analysis of a sample of serendipitous XMM clusters already provides interesting insights into the constraining power of the XXL survey. Subsequent analysis will use a larger sample extending to lower confidence detections and include additional observable information, potentially improving posterior uncertainties by roughly a factor of 3.
We present the Planck Sky Model (PSM), a parametric model for generating all-sky, few arcminute resolution maps of sky emission at submillimetre to centimetre wavelengths, in both intensity and ...polarisation. Several options are implemented to model the cosmic microwave background, Galactic diffuse emission (synchrotron, free-free, thermal and spinning dust, CO lines), Galactic H ii regions, extragalactic radio sources, dusty galaxies, and thermal and kinetic Sunyaev-Zeldovich signals from clusters of galaxies. Each component is simulated by means of educated interpolations/extrapolations of data sets available at the time of the launch of the Planck mission, complemented by state-of-the-art models of the emission. Distinctive features of the simulations are spatially varying spectral properties of synchrotron and dust; different spectral parameters for each point source; modelling of the clustering properties of extragalactic sources and of the power spectrum of fluctuations in the cosmic infrared background. The PSM enables the production of random realisations of the sky emission, constrained to match observational data within their uncertainties. It is implemented in a software package that is regularly updated with incoming information from observations. The model is expected to serve as a useful tool for optimising planned microwave and sub-millimetre surveys and testing data processing and analysis pipelines. It is, in particular, used to develop and validate data analysis pipelines within the Planck collaboration. A version of the software that can be used for simulating the observations for a variety of experiments is made available on a dedicated website.
The XXL Survey Eckert, D; Ettori, S; Coupon, J ...
Astronomy and astrophysics (Berlin),
08/2016, Letnik:
592
Journal Article
Recenzirano
Odprti dostop
Traditionally, galaxy clusters have been expected to retain all the material accreted since their formation epoch. For this reason, their matter content should be representative of the Universe as a ...whole, and thus their baryon fraction should be close to the Universal baryon fraction Omega sub(b)/ Omega sub(m). We make use of the sample of the 100 brightest galaxy clusters discovered in the XXL Survey to investigate the fraction of baryons in the form of hot gas and stars in the cluster population. Since it spans a wide range of mass (10 super(13)-10 super(15)M sub(middot in circle)) and redshift (0.05-1.1) and benefits from a large set of multiwavelength data, the XXL-100-GC sample is ideal for measuring the global baryon budget of massive halos. We measure the gas masses of the detected halos and use a mass-temperature relation directly calibrated using weak-lensing measurements for a subset of XXL clusters to estimate the halo mass. We find that the weak-lensing calibrated gas fraction of XXL-100-GC clusters is substantially lower than was found in previous studies using hydrostatic masses. Our best-fit relation between gas fraction and mass reads f sub(gas,500)= 0.055 sub(-0.006) super(+0.007) (M sub(500)/10 super(14)M sub(middot in circle)) super(0.21) sub(-0.10)+0 .11. The baryon budget of galaxy clusters therefore falls short of the Universal baryon fraction by about a factor of two at r sub(500,MT). Our measurements require a hydrostatic bias 1-b= M sub(X)/M sub(WL)= 0.72 sub(-0.07) super(+0.08) to match the gas fraction obtained using lensing and hydrostatic equilibrium, which holds independently of the instrument considered. Comparing our gas fraction measurements with the expectations from numerical simulations, we find that our results favour an extreme feedback scheme in which a significant fraction of the baryons are expelled from the cores of halos. This model is, however, in contrast with the thermodynamical properties of observed halos, which might suggest that weak-lensing masses are overestimated. In light of these results, we note that a mass bias 1-b= 0.58 as required to reconcile Planck cosmic microwave background and cluster counts should translate into an even lower baryon fraction, which poses a major challenge to our current understanding of galaxy clusters.
We present the first all-sky catalogue of galaxy clusters and cluster candidates obtained from joint X-ray-SZ detections using observations from the Planck satellite and the ROSAT all-sky survey ...(RASS). The catalogue contains 2323 objects and has been validated by careful cross-identification with previously known clusters. This validation shows that 1597 candidates correspond to already known clusters, 212 coincide with other cluster candidates still to be confirmed, and the remaining 514 are completely new detections. With respect to Planck catalogues, the ComPRASS catalogue is simultaneously more pure and more complete. Based on the validation results in the SPT and SDSS footprints, the expected purity of the catalogue is at least 84.5%, meaning that more than 365 clusters are expected to be found among the new or still-to-be-confirmed candidates with future validation efforts or specific follow-ups.
We determine the mass scale of Planck galaxy clusters using gravitational lensing mass measurements from the Cluster Lensing And Supernova survey with Hubble (CLASH). We have compared the lensing ...masses to the Planck Sunyaev-Zeldovich (SZ) mass proxy for 21 clusters in common, employing a Bayesian analysis to simultaneously fit an idealized CLASH selection function and the distribution between the measured observables and true cluster mass. We used a tiered analysis strategy to explicitly demonstrate the importance of priors on weak lensing mass accuracy. In the case of an assumed constant bias, bSZ, between true cluster mass, M500, and the Planck mass proxy, MPL, our analysis constrains 1−bSZ = 0.73 ± 0.10 when moderate priors on weak lensing accuracy are used, including a zero-mean Gaussian with standard deviation of 8% to account for possible bias in lensing mass estimations. Our analysis explicitly accounts for possible selection bias effects in this calibration sourced by the CLASH selection function. Our constraint on the cluster mass scale is consistent with recent results from the Weighing the Giants program and the Canadian Cluster Comparison Project. It is also consistent, at 1.34σ, with the value needed to reconcile the Planck SZ cluster counts with Planck’s base ΛCDM model fit to the primary cosmic microwave background anisotropies.
The combination of X-ray and Sunyaev–Zeldovich (SZ) observations can potentially improve the cluster detection efficiency, when compared to using only one of these probes, since both probe the same ...medium, the hot ionized gas of the intra-cluster medium. We present a method based on matched multifrequency filters (MMF) for detecting galaxy clusters from SZ and X-ray surveys. This method builds on a previously proposed joint X-ray–SZ extraction method and allows the blind detection of clusters, that is finding new clusters without knowing their position, size, or redshift, by searching on SZ and X-ray maps simultaneously. The proposed method is tested using data from the ROSAT all-sky survey and from the Planck survey. The evaluation is done by comparison with existing cluster catalogues in the area of the sky covered by the deep SPT survey. Thanks to the addition of the X-ray information, the joint detection method is able to achieve simultaneously better purity, better detection efficiency, and better position accuracy than its predecessor Planck MMF, which is based on SZ maps alone. For a purity of 85%, the X-ray–SZ method detects 141 confirmed clusters in the SPT region; to detect the same number of confirmed clusters with Planck MMF, we would need to decrease its purity to 70%. We provide a catalogue of 225 sources selected by the proposed method in the SPT footprint, with masses ranging between 0.7 and 14.5 ×1014 M⊙ and redshifts between 0.01 and 1.2.
We present the first cluster catalog extracted from combined space-based (
Planck
) and ground-based (South Pole Telescope; SPT-SZ) millimeter data. We developed and applied a matched multi-filter ...(MMF) capable of dealing with the different transfer functions and resolutions of the two datasets. We verified that it produces results consistent with publications from
Planck
and SPT collaborations when applied on the datasets individually. We also verified that
Planck
and SPT-SZ cluster fluxes are consistent with each other. When applied blindly to the combined dataset, the MMF generated a catalog of 419 detections (
S
/
N
> 5), of which 323 are already part of the SPT-SZ or PSZ2 catalogs; 54 are new SZ detections, which have been identified in other catalogs or surveys; and 42 are new unidentified candidates. The MMF takes advantage of the complementarity of the two datasets,
Planck
being particularly useful for detecting clusters at a low redshift (
z
< 0.3), while SPT is efficient at finding higher redshift (
z
> 0.3) sources. This work represents a proof of concept that blind cluster extraction can be performed on combined, inhomogeneous millimeter datasets acquired from space and ground. This result is of prime importance for planned ground-based cosmic microwave background (CMB) experiments (e.g., Simons Observatory, CMB-S4) and envisaged CMB space missions (e.g., PICO, Backlight) that will detect hundreds of thousands of clusters in the low mass regime (
M
500
≤ 10
14
M
⊙
), for which the various sources of intra-cluster emission (gas, dust, synchrotron) will be of the same order of magnitude and hence require broad ground and space frequency coverage with a comparable spatial resolution for adequate separation.
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