M. Pierre

The Spitzer Extragalactic Representative Volume Survey (SERVS): Survey Definition and Goals

We present the Spitzer Extragalactic Representative Volume Survey (SERVS), an 18 square degrees medium-deep survey at 3.6 and 4.5 microns with the post-cryogenic Spitzer Space Telescope to ~2 microJy (AB=23.1) depth of five highly observed astronomical fields (ELAIS-N1, ELAIS-S1, Lockman Hole, Chandra Deep Field South and XMM-LSS). SERVS is designed to enable the study of galaxy evolution as a function of environment from z~5 to the present day, and is the first extragalactic survey both large enough and deep enough to put rare objects such as luminous quasars and galaxy clusters at z>1 into their cosmological context. SERVS is designed to overlap with several key surveys at optical, near- through far-infrared, submillimeter and radio wavelengths to provide an unprecedented view of the formation and evolution of massive galaxies. In this paper, we discuss the SERVS survey design, the data processing flow from image reduction and mosaicing to catalogs, as well as coverage of ancillary data from other surveys in the SERVS fields. We also highlight a variety of early science results from the survey.

Combined analysis of weak lensing and X-ray blind surveys★

We present a joint weak lensing and X-ray analysis of 4 deg^2 from the CFHTLS and XMMLSS surveys. Our weak lensing analysis is the first analysis of a real survey using shapelets, a new generation weak lensing analysis method. We create projected mass maps of the images, and extract six weak-lensing-detected clusters of galaxies. We show that their counts can be used to constrain the power-spectrum normalization σ8 = 0.92^(+0.26)_(−0.30) for Ωm = 0.24. We show that despite the large scatter generally observed in the mass–temperature (M–T) relation derived from lensing masses, tight constraints on both its slope and normalization M∗ can be obtained with a moderate number of sources provided that the covered mass range is large enough. Adding clusters given by Bardeau et al. to our sample, we measure M∗ =2.71^(+0.79)_(−0.61) × 10^(14) h^(−1) Mסּ. Although they are dominated by shot noise and sample variance, our measurements are consistent with currently favoured values, and set the stage for future surveys. We thus investigate the dependence of those estimates on survey size, depth and integration time, for joint weak lensing and X-ray surveys. We show that deep surveys should be dedicated to the study of the physics of clusters and groups of galaxies. For a given exposure time, wide surveys provide a larger number of detected clusters and are therefore preferred for the measurement of cosmological parameters, such as σ8 and M∗.We show that a wide survey of a few hundred square degrees is needed to improve upon current measurements of these parameters. More ambitious surveys covering 7000 deg^2 will provide the 1 per cent accuracy in the estimation of the power-spectrum and the M–T relation normalizations.

The low frequency radio counterpart of the XMM Large Scale Structure Survey

The XMM Large-Scale Structure Survey (XMM-LSS) is a major project to map the large-scale structure of the universe out to cosmological distances. An 8° × 8° region will be surveyed by XMM with planned optical follow-up to produce a three-dimensional map of many hundreds of clusters out to a redshift of z = 1. To explore the relation of the large-scale structure to the location and properties of extragalactic radio sources, the XMM-LSS project also includes a low-frequency radio survey of this region. This combination will provide unprecedented insight into how the radio source formation and evolution are affected by the local environment. Here we present preliminary results from our 325 and 74 MHz surveys in this region. At 325 MHz, we have a flux limit of 4 mJy beam-1, a resolution of 63, and a total of 256 source detections over 5.6 deg2. At 74 MHz, we have a flux limit of 275 mJy beam-1, a resolution of 30, and a total of 211 source detections over 110 deg2. We describe these results and explore what they tell us about the population of extragalactic low-frequency radio sources. The 74 MHz survey represents the first presentation of a deep, subarcminute resolution survey at such a low frequency. This was made possible by recent advances in both hardware and data reduction algorithms, which we describe in detail.

Testing the galaxy cluster mass-observable relations at z = 1 with XMM-Newton and Chandra observations of XLSSJ022403.9-041328 ⋆ .

We present an analysis of deep XMM-Newton and Chandra observations of the z = 1.05 galaxy cluster XLSSJ022403.9-041328 (hereafter XLSSC 029), detected in the XMM-Newton Large Scale Structure survey. Density and temperature profiles of the X-ray emitting gas were used to perform a hydrostatic mass analysis of the system. This allowed us to measure the total mass and gas fraction in the cluster and define overdensity radii R 500 and R 2500 . The global properties of XLSSC 029 were measured within these radii and compared with those of the local population. The gas mass fraction was found to be consistent with local clusters. The mean metal abundance was 0.18 +0.17 -0.15 Z ⊙ , with the cluster core regions excluded, consistent with the predicted and observed evolution. The properties of XLSSC 029 were then used to investigate the position of the cluster on the M-kT, Y x -M and L x -M scaling relations. In all cases the observed properties of XLSSC 029 agreed well with the simple self-similar evolution of the scaling relations. This is the first test of the evolution of these relations at z > 1 and supports the use of the scaling relations in cosmological studies with distant galaxy clusters.

Distant galaxy clusters in the XMM large scale structure survey

Distant galaxy clusters provide important tests of the growth of large-scale structure in addition to highlighting the process of galaxy evolution in a consistently defined environment at large look-back time. We present a sample of 22 distant (z textgreater 0.8) galaxy clusters and cluster candidates selected from the 9 deg(2) footprint of the overlapping X-ray Multi Mirror (XMM) Large Scale Structure (LSS), CFHTLS-Wide and Spitzer-SWIRE surveys. Clusters are selected as extended X-ray sources with an accompanying overdensity of galaxies displaying optical to mid-infrared photometry consistent with z textgreater 0.8. Nine clusters have confirmed spectroscopic redshifts in the interval 0.8 textless z textless 1.2, four of which are presented here for the first time. A further 11 candidate clusters have between 8 and 10 band photometric redshifts in the interval 0.8 textless z textless 2.2, while the remaining two candidates do not have information in sufficient wavebands to generate a reliable photometric redshift. All of the candidate clusters reported in this paper are presented for the first time. Those confirmed and candidate clusters with available near-infrared photometry display evidence for a red sequence galaxy population, determined either individually or via a stacking analysis, whose colour is consistent with the expectation of an old, coeval stellar population observed at the cluster redshift. We further note that the sample displays a large range of red fraction values indicating that the clusters may be at different stages of red sequence assembly. We compare the observed X-ray emission to the flux expected from a suite of model clusters and find that the sample displays an effective mass limit M-200 similar to 1 x 10(14) M-circle dot with all clusters displaying masses consistent with M-200 textless 5 x 10(14) M-circle dot. This XMM distant cluster study represents a complete sample of X-ray-selected z textgreater 0.8 clusters. We discuss the importance of this sample to investigate the abundance of high-redshift clusters and to provide a relatively unbiased view of distant cluster galaxy populations.

The Spitzer Extragalactic Representative Volume Survey (SERVS): Survey Definition and Goals (PASP, 124, 714, [2012])

The print version of this article contained some errors and omissions by the publishers and authors

The XXL Survey: XXXIII. Chandra Constraints on the AGN Contamination of

Context. The XMM-XXL survey has used observations from the XMM-Newton observatory to detect clusters of galaxies over a wide range in mass and redshift. The moderate PSF (FWHM ~ 6″ on-axis) of XMM-Newton means that point sources within or projected onto a cluster may not be separated from the cluster emission, leading to enhanced luminosities and affecting the selection function of the cluster survey.Aims. We present the results of short Chandra observations of 21 galaxy clusters and cluster candidates at redshifts z > 1 detected in the XMM-XXL survey in X-rays or selected in the optical and infra-red.Methods. With the superior angular resolution of Chandra, we investigate whether there are any point sources within the cluster region that were not detected by the XMM-XXL analysis pipeline, and whether any point sources were misclassified as distant clusters.Results. Of the 14 X-ray selected clusters, 9 are free from significant point source contamination, either having no previously unresolved sources detected by Chandra or with less than about 10% of the reported XXL cluster flux being resolved into point sources. Of the other five sources, one is significantly contaminated by previously unresolved AGN, and four appear to be AGN misclassified as clusters. All but one of these cases are in the subset of less secure X-ray selected cluster detections and the false positive rate is consistent with that expected from the XXL selection function modelling. We also considered a further seven optically selected cluster candidates associated with faint XXL sources that were not classed as clusters. Of these, three were shown to be AGN by Chandra, one is a cluster whose XXL survey flux was highly contaminated by unresolved AGN, while three appear to be uncontaminated clusters. By decontaminating and vetting these distant clusters, we provide a pure sample of clusters at redshift z > 1 for deeper follow-up observations, and demonstrate the utility of using Chandra snapshots to test for AGN in surveys with high sensitivity but poor angular resolution.Key words: cosmology: observations / galaxies: clusters: general / X-rays: galaxies: clusters★ Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA, and Chandra, a NASA science mission with instruments and contributions directly funded by NASA.

z>1

We present the X-ray source detection procedure that we have developed for the purpose of assembling and characterizing controlled samples of cluster of galaxies for the XMM Large Scale Structure Survey. We describe how we model the selection function by means of simulations: this leads us to define source classes rather than flux limited samples. Focussing on the CFHTLS D1 area, our compilation suggests a cluster density higher than previously determined from the deep ROSAT surveys above a flux of 2.10^(-14) erg cm-2 s-1. We also present the L-T relation for the 9 brightest objects in the area. The slope is in good agreement with the local correlation. The relation shows luminosity enhancement for some of the 0.15<z<0.35 objects having 1<T<2 keV, a population that the XMM-LSS is for the first time systematically unveiling.

XXL Galaxy Clusters

The main goal of this study is to investigate the LF of a sample of 142 X-ray selected clusters, with spectroscopic redshift confirmation and a well defined selection function, spanning a wide redshift and mass range, and to test the LF dependence on cluster global properties, in a homogeneous and unbiased way. Our study is based on the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) photometric galaxy catalogue,associated with photometric redshifts. We constructed LFs inside a scaled radius using a selection in photometric redshift around the cluster spectroscopic redshift in order to reduce projection effects. The width of the photometric redshift selection was carefully determined to avoid biasing the LF and depended on both the cluster redshift and the galaxy magnitudes. The purity was then enhanced by applying a precise background subtraction. We constructed composite luminosity functions (CLFs) by stacking the individual LFs and studied their evolution with redshift and richness, analysing separately the brightest cluster galaxy (BCG) and non-BCG members. We fitted the dependences of the CLFs and BCG distributions parameters with redshift and richness conjointly in order to distinguish between these two effects. We find that the usual photometric redshift selection methods can bias the LF estimate if the redshift and magnitude dependence of the photometric redshift quality is not taken into account. Our main findings concerning the evolution of the galaxy luminosity distribution with redshift and richness are that, in the inner region of clusters and in the redshift-mass range we probe (about

The XMM-LSS cluster sample and its cosmological applications: Prospects for the XMM next decade

0<z<1