References of "Maccagni, D"
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See detailThe XMM-LSS survey: optical assessment and properties of different X-ray selected cluster classes
Adami, C.; Mazure, A.; Pierre, M. et al

in Astronomy and Astrophysics (2011), 526(A18), 36

XMM and Chandra opened a new area for the study of clusters of galaxies. Not only for cluster physics but also, for the detection of faint and distant clusters that were inaccessible with previous ... [more ▼]

XMM and Chandra opened a new area for the study of clusters of galaxies. Not only for cluster physics but also, for the detection of faint and distant clusters that were inaccessible with previous missions. This article presents 66 spectroscopically confirmed clusters (0.05<z<1.5) within an area of 6 deg2 enclosed in the XMM-LSS survey. Almost two thirds have been confirmed with dedicated spectroscopy only and 10% have been confirmed with dedicated spectroscopy supplemented by literature redshifts. Sub-samples, or classes, of extended-sources are defined in a two-dimensional X-ray parameter space allowing for various degrees of completeness and contamination. We describe the procedure developed to assess the reality of these cluster candidates using the CFHTLS photometric data and spectroscopic information from our own follow-up campaigns. Most of these objects are low mass clusters, hence constituting a still poorly studied population. In a second step, we quantify correlations between the optical properties such as richness or velocity dispersion and the cluster X-ray luminosities. We examine the relation of the clusters to the cosmic web. Finally, we review peculiar structures in the surveyed area like very distant clusters and fossil groups. [less ▲]

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See detailThe XMM-LSS survey: the Class 1 cluster sample over the initial 5 deg(2) and its cosmological modelling
Pacaud, F.; Pierre, M.; Adami, C. et al

in Monthly Notices of the Royal Astronomical Society (2007), 382(3), 1289-1308

We present a sample of 29 galaxy clusters from the XMM-LSS survey over an area of some 5 deg(2) out to a redshift of z = 1.05. The sample clusters, which represent about half of the X-ray clusters ... [more ▼]

We present a sample of 29 galaxy clusters from the XMM-LSS survey over an area of some 5 deg(2) out to a redshift of z = 1.05. The sample clusters, which represent about half of the X-ray clusters identified in the region, follow well-defined X-ray selection criteria and are all spectroscopically confirmed. For all clusters, we provide X-ray luminosities and temperatures as well as masses, obtained from dedicated spatial and spectral fitting. The cluster distribution peaks around z = 0.3 and T = 1.5 keV, half of the objects being groups with a temperature below 2 keV. Our L-X-T(z) relation points towards self-similar evolution, but does not exclude other physically plausible models. Assuming that cluster scaling laws follow self-similar evolution, our number density estimates up to z = 1 are compatible with the predictions of the concordance cosmology and with the findings of previous ROSAT surveys. Our well-monitored selection function allowed us to demonstrate that the inclusion of selection effects is essential for the correct determination of the evolution of the L-X-T relation, which may explain the contradictory results from previous studies. Extensive simulations show that extending the survey area to 10 deg(2) has the potential to exclude the non-evolution hypothesis, but those constraints on more refined intracluster medium models will probably be limited by the large intrinsic dispersion of the L-X-T relation, whatever be the sample size. We further demonstrate that increasing the dispersion in the scaling laws increases the number of detectable clusters, hence generating further degeneracy [in addition to sigma(8), Omega(m), L-X-T(z)] in the cosmological interpretation of the cluster number counts. We provide useful empirical formulae for the cluster mass-flux and mass-count rate relations as well as a comparison between the XMM-LSS mass sensitivity and that of forthcoming Sunyaev-Zel'dovich surveys. [less ▲]

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See detailThe XMM-Large scale structure catalogue: X-ray sources and associated optical data. Version I
Pierre, M.; Chiappetti, L.; Pacaud, F. et al

in Monthly Notices of the Royal Astronomical Society (2007), 382(1), 279-290

Following the presentation of the XMM-Large Scale Structure (XMM-LSS) survey X-ray source detection package by Pacaud et al., we provide the source lists for the first surveyed 5.5 deg(2). The catalogues ... [more ▼]

Following the presentation of the XMM-Large Scale Structure (XMM-LSS) survey X-ray source detection package by Pacaud et al., we provide the source lists for the first surveyed 5.5 deg(2). The catalogues pertain to the [0.5-2] and [2-10] keV bands and contain in total 3385 pointlike or extended sources above a detection likelihood of 15 in either band. The agreement with deep log N-log S is excellent. The main parameters considered are position, count rate, source extent with associated likelihood values. A set of additional quantities such as astrometric corrections and fluxes are further calculated while errors on the position and count rate are deduced from simulations. We describe the construction of the band-merged catalogue allowing rapid subsample selection and easy cross-correlation with external multiwavelength catalogues. A small optical Canada-France-Hawaii Telescope Legacy Survey multiband subset of objects are associated with each source along with an X-ray/optical overlay. We make the full X-ray images available in FITS format. The data are available at the Centre de Donnees de Strasbourg and, in a more extended form, at the Milan XMM-LSS survey data base. [less ▲]

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See detailXMM-LSS survey: AGN classifications (Garcet+, 2007)
Garcet, O.; Gandhi, P.; Gosset, Eric ULg et al

Textual, factual or bibliographical database (2007)

We have used the most up-to-date X-ray catalog (Pierre et al., 2007, Cat. J/MNRAS/382/279) to define a sample of 612 X-ray selected point-like sources which have both a log-likelihood of detection >20 ... [more ▼]

We have used the most up-to-date X-ray catalog (Pierre et al., 2007, Cat. J/MNRAS/382/279) to define a sample of 612 X-ray selected point-like sources which have both a log-likelihood of detection >20 (this roughly corresponds to >3{sigma}) in the [2-10]keV band (see Pacaud et al., 2006MNRAS.372..578P, for full details), and a total number of counts >80 in the [0.5-10]keV band. (1 data file). [less ▲]

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See detailXMM-LSS catalogue. Version I. (Pierre+, 2007)
Pierre, M.; Chiappetti, L.; Pacaud, F. et al

Textual, factual or bibliographical database (2007)

We provide the source list for the first 5.5 surveyed square degrees of the XMM-LSS, with a total of 3385 point-like or extended sources above a detection likelihood of 15 in either 0.5-2 or 2-10keV bands ... [more ▼]

We provide the source list for the first 5.5 surveyed square degrees of the XMM-LSS, with a total of 3385 point-like or extended sources above a detection likelihood of 15 in either 0.5-2 or 2-10keV bands. The table at CDS contains the main parameters, while further parameters and data products (X-ray images and optical thumbnails) are available in the Milan XMM-LSS database site. (1 data file). [less ▲]

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See detail3{sigma} hard sample of XMDS survey (Tajer+, 2007)
Tajer, M.; Polletta, M.; Chiappetti, L. et al

Textual, factual or bibliographical database (2007)

Our goal is to probe the populations of obscured and unobscured AGN investigating their optical-IR and X-ray properties as a function of X-ray flux, luminosity and redshift within a hard X-ray selected ... [more ▼]

Our goal is to probe the populations of obscured and unobscured AGN investigating their optical-IR and X-ray properties as a function of X-ray flux, luminosity and redshift within a hard X-ray selected sample with wide multiwavelength coverage. We selected a sample of 136 X-ray sources detected at a significance of >=3{sigma} in the 2-10keV band (F[SUB]2-10[/SUB]>~10[SUP]-14[/SUP]erg/cm[SUP]2[/SUP]/s) in a ~1deg[SUP]2[/SUP] area in the XMM Medium Deep Survey (XMDS, Cat. ). The XMDS area is covered with optical photometry from the VVDS and CFHTLS surveys and infrared Spitzer data from the SWIRE survey. Based on the X-ray luminosity and X-ray to optical ratio, 132 sources are likely AGN, of which 122 have unambiguous optical - IR identification. The observed optical and IR spectral energy distributions of all identified sources are fitted with AGN/galaxy templates in order to classify them and compute photometric redshifts. X-ray spectral analysis is performed individually for sources with a sufficient number of counts and using a stacking technique for subsamples of sources at different flux levels. Hardness ratios are used to estimate X-ray absorption in individual weak sources. (1 data file). [less ▲]

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See detailObscured and unobscured AGN populations in a hard-X-ray selected sample of the XMDS survey
Tajer, M.; Polletta, M.; Chiappetti, L. et al

in Astronomy and Astrophysics (2007), 467(1), 73-91

Aims. Our goal is to probe the populations of obscured and unobscured AGN investigating their optical-IR and X-ray properties as a function of X-ray flux, luminosity and redshift within a hard X-ray ... [more ▼]

Aims. Our goal is to probe the populations of obscured and unobscured AGN investigating their optical-IR and X-ray properties as a function of X-ray flux, luminosity and redshift within a hard X-ray selected sample with wide multiwavelength coverage. Methods. We selected a sample of 136 X-ray sources detected at a significance of >= 3 sigma in the 2-10 keV band (F2-10 greater than or similar to 10(-1)4 erg cm(-2) s(-1)) in a similar to 1 deg(2) area in the XMM Medium Deep Survey (XMDS). The XMDS area is covered with optical photometry from the VVDS and CFHTLS surveys and infrared Spitzer data from the SWIRE survey. Based on the X-ray luminosity and X-ray to optical ratio, 132 sources are likely AGN, of which 122 have unambiguous optical - IR identification. The observed optical and IR spectral energy distributions of all identified sources are fitted with AGN/galaxy templates in order to classify them and compute photometric redshifts. X-ray spectral analysis is performed individually for sources with a sufficient number of counts and using a stacking technique for subsamples of sources at different flux levels. Hardness ratios are used to estimate X-ray absorption in individual weak sources. Results. 70% of the AGN are fitted by a type 2 AGN or a star forming galaxy template. We group them together in a single class of "optically obscured" AGN. These have "red" optical colors and in about 60% of cases show significant X-ray absorption (N-H > 10(22) cm(-2)). Sources with SEDs typical of type 1 AGN have "blue" optical colors and exhibit X-ray absorption in about 30% of cases. The stacked X-ray spectrum of obscured AGN is flatter than that of type 1 AGN and has an average spectral slope of Gamma = 1.6. The subsample of objects fitted by a star forming galaxy template has an even harder stacked spectrum, with Gamma similar to 1.2-1.3. The obscured fraction is larger at lower fluxes, lower redshifts and lower luminosities. X-ray absorption is less common than "optical" obscuration and its incidence is nearly constant with redshift and luminosity. This implies that at high luminosities X-ray absorption is not necessarily related to optical obscuration. The estimated surface densities of obscured, unobscured AGN and type 2 QSOs are respectively 138, 59 and 35 deg(-2) at F > 10-14 erg cm(-2) s(-1). [less ▲]

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See detailSpectral Energy Distributions of Hard X-Ray Selected Active Galactic Nuclei in the XMM-Newton Medium Deep Survey
Polletta, M.; Tajer, M.; Maraschi, L. et al

in Astrophysical Journal (2007), 663

We present the SEDs of a hard X-ray selected sample containing 136 sources with F[SUB]2-10keV[/SUB]>10[SUP]-14[/SUP] erg cm[SUP]-2[/SUP] s[SUP]-1[/SUP] 132 are AGNs. The sources are detected in a 1 deg ... [more ▼]

We present the SEDs of a hard X-ray selected sample containing 136 sources with F[SUB]2-10keV[/SUB]>10[SUP]-14[/SUP] erg cm[SUP]-2[/SUP] s[SUP]-1[/SUP] 132 are AGNs. The sources are detected in a 1 deg[SUP]2[/SUP] area of the XMM-Newton Medium Deep Survey where optical data from the VVDS and CFHTLS and infrared data from the SWIRE survey are available. Based on a SED fitting technique we derive photometric redshifts with sigma(1+z)=0.11 and 6% of outliers and identify AGN signatures in 83% of the objects. This fraction is higher than derived when a spectroscopic classification is available. The remaining 17[SUP]+9[/SUP][SUB]-6[/SUB]% of AGNs show star-forming galaxy SEDs (SF class). The sources with AGN signatures are divided in two classes, AGN1 (33[SUP]+6[/SUP][SUB]-1[/SUB]%) and AGN2 (50[SUP]+6[/SUP][SUB]-11[/SUB]%). The AGN1 and AGN2 classes include sources whose SEDs are fitted by type 1 and type 2 AGN templates, respectively. On average, AGN1s show soft X-ray spectra, consistent with being unabsorbed, while AGN2s and SFs show hard X-ray spectra, consistent with being absorbed. The analysis of the average SEDs as a function of X-ray luminosity shows a reddening of the infrared SEDs, consistent with a decreasing contribution from the host galaxy at higher luminosities. The AGNs in the SF classes are likely obscured in the mid-infrared, as suggested by their low L[SUB]3-20mum[/SUB]/L[SUP]corr[/SUP][SUB]0.5-10keV[/SUB] ratios. We confirm the previously found correlation for AGNs between the radio luminosity and the X-ray and the mid-infrared luminosities. The X-ray-radio correlation can be used to identify heavily absorbed AGNs. However, the estimated radio fluxes for the missing AGN population responsible for the bulk of the background at E>10 keV are too faint to be detected even in the deepest current radio surveys. [less ▲]

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See detailThe XMM large scale structure survey: optical vs. X-ray classifications of active galactic nuclei and the unified scheme
Garcet, Olivier ULg; Gandhi, P.; Gosset, Eric ULg et al

in Astronomy and Astrophysics (2007), 474

Aims.Our goal is to characterize AGN populations by comparing their X-ray and optical classifications within the framework of the standard orientation-based unified scheme. Methods: We present a sample of ... [more ▼]

Aims.Our goal is to characterize AGN populations by comparing their X-ray and optical classifications within the framework of the standard orientation-based unified scheme. Methods: We present a sample of 99 spectroscopically identified (R <= 22 mag) X-ray selected point sources in the XMM-LSS survey which are significantly detected (>=3sigma) in the [ 2-10] keV band with fluxes between 8 × 10[SUP]-15[/SUP] and 8 × 10[SUP]-14[/SUP] erg s[SUP]-1[/SUP] cm[SUP]-2[/SUP], and which have more than 80 counts. We have compared their X-ray and optical classifications. To this end, we performed an X-ray spectral analysis for all of these 99 X-ray sources in order to assess whether they are intrinsically absorbed or not. The X-ray classification is based on the measured intrinsic column density. The optical classification is based on the measured FWHM of the permitted emission lines, the absence of broad lines being due to obscuration within the framework of the standard AGN unified scheme. Results: Introducing the fourfold point correlation coefficient r, we find a mild correlation between the X-ray and the optical classifications (r = 0.28), as up to 32 X-ray sources out of 99 have differing X-ray and optical classifications: on one hand, 10% of the type 1 sources (7/32) present broad emission lines in their optical spectra and strong absorption (N{H}[SUP]int[/SUP] >= 10[SUP]22[/SUP] cm[SUP]-2[/SUP]) in the X-rays. These objects are highly luminous AGN lying at high redshift and thus dilution effects by the host galaxy light are totally ruled out, their discrepant nature being an intrinsic property instead. Their X-ray luminosities and redshifts distributions are consistent with those of the unabsorbed X-ray sources with broad emission lines (L{2-10} 4 × 10[SUP]44[/SUP] erg s[SUP]-1[/SUP]; z 1.9). On the other hand, 25/32 are moderate luminosity (L{2-10} <= 5 × 10[SUP]43[/SUP] erg s[SUP]-1[/SUP]) AGN, which are both unabsorbed in the X-rays and only present narrow emission lines in their optical spectra. Based on their line ratios in the optical, the majority of them have an optical spectrum which is more representative of the host galaxy rather than of a reddened AGN. We finally infer that dilution of the AGN by the host galaxy seems to account for their nature. 5/25 have been defined as Seyfert 2 based on their optical spectra. In conclusion, most of these 32 discrepant cases can be accounted for by the standard AGN unified scheme, as its predictions are not met for only 12% of the 99 X-ray sources. Table 4 and Figs. [see full text]-[see full text] are only available in electronic form at http://www.aanda.org [less ▲]

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See detailThe XMM Large-Scale Structure survey: a well-controlled X-ray cluster sample over the D1 CFHTLS area
Pierre, M.; Pacaud, F.; Duc, P. A. et al

in Monthly Notices of the Royal Astronomical Society (2006), 372(2), 591-608

We present the XMM Large-Scale Structure Survey (XMM-LSS) cluster catalogue corresponding to the Canada-France-Hawaii Telescope Legacy Survey D1 area. The list contains 13 spectroscopically confirmed, X ... [more ▼]

We present the XMM Large-Scale Structure Survey (XMM-LSS) cluster catalogue corresponding to the Canada-France-Hawaii Telescope Legacy Survey D1 area. The list contains 13 spectroscopically confirmed, X-ray selected galaxy clusters over 0.8 deg(2) to a redshift of unity and so constitutes the highest density sample of clusters to date. Cluster X-ray bolometric luminosities range from 0.03 to 5 x 10(44) erg s(-1). In this study, we describe our catalogue construction procedure: from the detection of X-ray cluster candidates to the compilation of a spectroscopically confirmed cluster sample with an explicit selection function. The procedure further provides basic X-ray products such as cluster temperature, flux and luminosity. We detected slightly more clusters with (0.5-2.0 keV) X-ray fluxes of > 2 x 10(-14) erg s(-1) cm(-2) than we expected based on expectations from deep ROSAT surveys. We also present the luminosity-temperature relation for our nine brightest objects possessing a reliable temperature determination. The slope is in good agreement with the local relation, yet compatible with a luminosity enhancement for the 0.15 < z < 0.35 objects having 1 < T < 2 keV, a population that the XMM-LSS is identifying systematically for the first time. The present study permits the compilation of cluster samples from XMM images whose selection biases are understood. This allows, in addition to studies of large-scale structure, the systematic investigation of cluster scaling law evolution, especially for low mass X-ray groups which constitute the bulk of our observed cluster population. All cluster ancillary data (images, profiles, spectra) are made available in electronic form via the XMM-LSS cluster data base. [less ▲]

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See detailThe XMM large scale structure survey: properties and two-point angular correlations of point-like sources
Gandhi, P.; Garcet, Olivier ULg; Disseau, L. et al

in Astronomy and Astrophysics (2006), 457(2), 393-404

We analyze X-ray sources detected over 4.2 pseudo-contiguous sq. deg. in the 0.5-2 keV and 2-10 keV bands down to fluxes of 2× 10[SUP]-15[/SUP] and 8× 10[SUP]-15[/SUP] erg s[SUP]-1[/SUP] cm[SUP]-2[/SUP ... [more ▼]

We analyze X-ray sources detected over 4.2 pseudo-contiguous sq. deg. in the 0.5-2 keV and 2-10 keV bands down to fluxes of 2× 10[SUP]-15[/SUP] and 8× 10[SUP]-15[/SUP] erg s[SUP]-1[/SUP] cm[SUP]-2[/SUP] respectively, as part of the XMM-Newton Large Scale Structure Survey. The log N-log S in both bands shows a steep slope at bright fluxes, but agrees well with other determinations below ~2 × 10[SUP]-14[/SUP] erg s[SUP]-1[/SUP] cm[SUP]-2[/SUP]. The detected sources resolve close to 30 per cent of the X-ray background in the 2-10 keV band. We study the two-point angular clustering of point sources using nearest neighbours and correlation function statistics and find a weak, positive signal for ~1130 sources in the 0.5-2 keV band, but no correlation for ~400 sources in the 2-10 keV band below scales of 100 arcsec. A sub-sample of ~200 faint sources with hard X-ray count ratios, that is likely to be dominated by obscured AGN, does show a positive signal with the data allowing for a large angular correlation length, but only at the ~2 (3)sigma level, based on re-sampling (Poisson) statistics. We discuss possible implications and emphasize the importance of wider, complete surveys in order to fully understand the large scale structure of the X-ray sky. [less ▲]

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See detailAngular Clustering of Obscured Active Galactic Nuclei
Gandhi, Poshak; Garcet, O.; Disseau, L. et al

in Bulletin of the American Astronomical Society, Vol. 38 (2006, September 01)

We describe the properties of X-ray point-like sources detected over 4.2 sq. degs. of the largest contiguous survey with XMM-Newton to date (the XMM-LSS survey) to fluxes of F[SUB]2-10 keV[/SUB] 8x10[SUP ... [more ▼]

We describe the properties of X-ray point-like sources detected over 4.2 sq. degs. of the largest contiguous survey with XMM-Newton to date (the XMM-LSS survey) to fluxes of F[SUB]2-10 keV[/SUB] 8x10[SUP]-15[/SUP] erg/s/cm[SUP]2[/SUP] and F[SUB]0.5-2 keV[/SUB] 2x10[SUP]-15[/SUP] erg/s/cm[SUP]2[/SUP] respectively. For 1200 sources in the soft band, we find a two-point angular correlation function (ACF) signal similar to previous work, but no correlation for 400 sources in the hard band. A sample of 200 faint sources with hard X-ray spectra does show a 2-3 sigma positive signal with a power-law normalization theta[SUB]0[/SUB]>40 arcsec. We discuss implications, including the fact that a large correlation length for obscured AGN is inconsistent with simple AGN Unification based on orientation only. [less ▲]

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See detailThe XMM-LSS survey - The XMDS/VVDS 4 sigma catalogue
Chiappetti, L.; Tajer, M.; Trinchieri, G. et al

in Astronomy and Astrophysics (2005), 439(1), 413-425

We present a first catalogue of X-ray sources resulting from the central area of the XMM-LSS (Large Scale Structure survey). We describe the reduction procedures and the database tools we developed and ... [more ▼]

We present a first catalogue of X-ray sources resulting from the central area of the XMM-LSS (Large Scale Structure survey). We describe the reduction procedures and the database tools we developed and used to derive a well defined catalogue of X-ray sources. The present catalogue is limited to a sub-sample of 286 sources detected at 4 sigma in the 1 deg(2) area covered by the photometric VVDS (VIRMOS VLT Deep Survey), which allows us to provide optical and radio identifications. We also discuss the X-ray properties of a larger X-ray sample of 536 sources detected at > 4 sigma in the full 3 deg(2) area of the XMM Medium Deep Survey (XMDS) independently of the optical identification. We also derive the log N - log S relationship for a sample of more than one thousand sources that we discuss in the context of other surveys at similar fluxes. [less ▲]

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See detailXMDS/VVDS 4{sigma} catalogue (Chiappetti+, 2005)
Chiappetti, L.; Tajer, M.; Trinchieri, G. et al

Textual, factual or bibliographical database (2005)

We present a catalogue of 286 X-ray sources with their optical identification taken from the XMDS survey (using the XMM-Newton EPIC instrument). This first version is limited to sources detected at 4 ... [more ▼]

We present a catalogue of 286 X-ray sources with their optical identification taken from the XMDS survey (using the XMM-Newton EPIC instrument). This first version is limited to sources detected at 4{sigma} at least in one energy band, AND falling in the area covered by the optical VVDS survey. (1 data file). [less ▲]

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See detailPreliminary Results from the XMM Medium Deep Survey
Maraschi, L.; Tajer, M.; Trinchieri, G. et al

in Mújica, Raúl; Maiolino, Roberto (Eds.) Multiwavelength AGN Surveys, Proceedings of the Guillermo Haro Conference (2004, January 01)

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See detailThe XMM Large Scale Structure Survey and its multi-lambda follow-up
Pierre, M.; Alloin, D.; Altieri, B. et al

Article for general public (2001)

We present a unique European project which aims at mapping the matter distribution in the distant universe from hundreds of megaparsecs to galaxy scales. This comprehensive scientific approach constitutes ... [more ▼]

We present a unique European project which aims at mapping the matter distribution in the distant universe from hundreds of megaparsecs to galaxy scales. This comprehensive scientific approach constitutes a new step in the synergy between space- and ground-based observatory resources and therefore a building block of the forthcoming Virtual Observatory. [less ▲]

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