In this paper we investigate the properties of low X-ray-to-optical flux ratio sources detected in a wide-area (2.5{deg}^2^) shallow [fX(0.5-8keV)~10^-14^erg/s/cm^2^] XMM-Newton survey. We find a total of 26 sources (5 per cent of the total X-ray-selected population) with log(fX)/f(opt)<-0.9 to the above flux limit. Optical spectroscopy is available for 20 of these low X-ray-to-optical flux ratio objects.
We present an analysis of the X-ray spectral properties of 61 hard X-ray (2-8keV) selected sources from the bright XMM-Newton/2dF (f(2-8keV)>10^-14^erg/cm^2^/s) survey. This comprises nine XMMNewton pointings in the North Galactic Pole region (~1.6deg^2^) and overlaps with the SDSS, 2QZ and 2dFGRS surveys. Our sources contribute about 50 per cent of the 2-10keV X-ray background down to the flux limit of 10^-14^erg/cm^2^/s. The hardness ratio distribution of the sample suggests a deficit of heavily absorbed sources. Spectroscopic identifications exist for 34 sources.
The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST) surveys the most populated ~5 square degrees of the Taurus Molecular Cloud, using the XMM-Newton X-ray observatory to study the thermal structure, variability, and long-term evolution of hot plasma, to investigate the magnetic dynamo, and to search for new potential members of the association. We present overall correlations with fundamental stellar parameters that were derived from the previous literature. The present overview paper introduces the project and provides the basic results from the X-ray analysis of all sources detected in the XEST survey. Comprehensive tables summarize the stellar properties of all targets surveyed. The survey goes deeper than previous X-ray surveys of Taurus by about an order of magnitude and for the first time systematically accesses very faint and strongly absorbed TMC objects. We find a detection rate of 85% and 98% for classical and weak-line T Tauri stars (CTTS resp. WTTS), and identify about half of the surveyed protostars and brown dwarfs. Overall, 136 out of 169 surveyed stellar systems are detected. We describe an X-ray luminosity vs. mass correlation, discuss the distribution of X-ray-to-bolometric luminosity ratios, and show evidence for lower X-ray luminosities in CTTS compared to WTTS.
We present the first results from the XMM-Newton Galactic Plane Survey (XGPS). In the first phase of the programme, 22 pointings were used to cover a region of approximately 3 deg^2^between 19{deg} and 22{deg} in Galactic longitude and +/-0.6{deg} in latitude. In total we have resolved over 400 point X-ray sources, at >=5{sigma} significance, down to a flux limit of ~2x10^-14^erg/s/cm^2^(2-10 keV).
This table contains the first results from the XMM-Newton Galactic Plane Survey (XGPS). In the first phase of the program, 22 pointings were used to cover a region of approximately 3 square degrees between 19 and 22 degrees in Galactic Longitude and +/-0.6 degrees in Galactic Latitude. In total, over 400 point X-ray sources have been resolved at >=5-sigma significance, down to a flux limit of ~2 x 10<sup>-14</sup> erg/s/cm<sup>2</sup> (2-10 keV). The sources exhibit a very wide range of spectral hardness, with interstellar absorption identified as a major influence. The source populations detected in the soft (0.4 - 2 keV) band and hard (2 - 6 keV) band show surprisingly little overlap. The majority of the soft sources appear to be associated with relatively nearby stars with active stelaar coronae, judging from their high coincidence with bright stellar counterparts. The combination of the XGPS measurements in the hard X-ray band with the results from earlier surveys carried out by ASCA and Chandra reveals the form of the low-latitude X-ray source counts over 4 decades of flux. It appears that extragalactic sources dominate below ~10<sup>-13</sup> erg/s/cm<sup>2</sup> (2-10 keV), with a predominantly Galactic source population present above this flux threshold. The nature of the faint Galactic population observed by XMM-Newton remains uncertain, although cataclysmic variables and RS CVn systems may contribute substantially. This table was created by the HEASARC in February 2005 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/351/31/tablea1">CDS Catalog J/MNRAS/351/31/tablea1</a>.dat. This is a service provided by NASA HEASARC .
We present new X-ray temperatures and improved X-ray luminosity estimates for 15 new and archival XMM-Newton observations of galaxy clusters at intermediate redshift with mass and luminosities near the galaxy group/cluster division (M_2500_<2.4x10_70_^-1^M_{sun}_, L<2x10^44^erg/s, 0.3<z<0.6). These clusters have weak-lensing mass measurements based on Hubble Space Telescope observations of clusters representative of an X-ray-selected sample (the ROSAT 160SD survey). The angular resolution of XMM-Newton allows us to disentangle the emission of these galaxy clusters from nearby point sources, which significantly contaminated previous X-ray luminosity estimates for 6 of the 15 clusters. We extend cluster scaling relations between X-ray luminosity, temperature, and weak-lensing mass for low-mass, X-ray-selected clusters out to redshift ~0.45. These relations are important for cosmology and the astrophysics of feedback in galaxy groups and clusters. Our joint analysis with a sample of 50 clusters in a similar redshift range but with larger masses (M_500_<21.9x10^14^M_{sun}_, 0.15<=z<=0.55) from the Canadian Cluster Comparison Project finds that within r_2500_, M{prop.to}L^0.44+/-0.05^, T{prop.to}L^0.23+/-0.02^, and M{prop.to}T^1.9+/-0.2^. The estimated intrinsic scatter in the M-L relation for the combined sample is reduced to {sigma}_log(M|L)_=0.10, from {sigma}_log(M|L)_=0.26 with the original ROSAT measurements. We also find an intrinsic scatter for the T-L relation, {sigma}_log(T|L)_=0.07+/-0.01.
We present the results of a deep X-ray survey conducted with XMM-Newton, centred on the UK ROSAT 13^H^ deep field area. This region covers 0.18{deg}^2^, and is the first of the two areas covered with XMM-Newton as part of an extensive multi-wavelength survey designed to study the nature and evolution of the faint X-ray source population.
XMM-Newton Large-Scale Structure Deep Full-Exposure X-Ray Source Catalog
Short Name:
XMMLSSDEEP
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains some of the X-ray results from the final release of the multiwavelength XMM-Large Scale Structure (LSS) data set, covering the full survey area of 11.1 deg<sup>2</sup>. The 124 XMM-Newton observations used in the complete XMM-LSS are described in Section 2 and Table 1 of the primary reference paper (Chiappetti et al. 2013, hereafter Paper II). The X-ray data were processed with the latest XMM-LSS XAMIN pipeline version. The catalogs in Paper II supersede the catalog from the first paper in this series (Paper I: Pierre et al. 2007, MNRAS, 382, 279, available at the HEASARC as the XMMLSS table) pertaining to the initial 5 deg<sup>2</sup>. The authors provide X-ray source lists in the customary soft and hard energy bands (0.5-2 keV and 2-10 keV, respectively) for a total of 6721 objects in the deep full-exposure 2XLSSd catalog presented in this table, and 5572 objects in the catalog limited to 10 ks exposures (available at the HEASARC as the XMMLSS10KS table), above a detection likelihood of 15 in at least one band. At the XMMLSS web site which they maintain (<a href="http://cosmosdb.iasf-milano.inaf.it/XMM-LSS/">http://cosmosdb.iasf-milano.inaf.it/XMM-LSS/</a>), the authors also provide a multiwavelength catalog, cross-correlating their list of X-ray sources with infrared, near-infrared, optical and ultraviolet catalogs. Customary data products, such as X-ray FITS images and thumbnail images from the Canada-France-Hawaii Telescope Legacy Survey and the Spitzer Wide-Area Infrared Extragalactic Survey, are made available there, together with their data base in Milan, which can be queried interactively. In this table, the authors provide the source list for the full area (11.1 square degrees) of the XMM-LSS, with a total of 6721 point-like or extended sources above a detection likelihood of 15 in either the 0.5-2 or 2-10 keV bands. This table, the 2XLSSd "deep catalog" version containing the result of the analysis of the full-length exposures, lists the main X-ray parameters, while further multiwavelength parameters and data products (X-ray images and optical/IR thumbnails) are available at the Milan XMM-LSS database site referenced above. It supersedes the first XMM-LSS version (Pierre et al. 2007, available at the HEASARC as the XMMLSS table). Analogously to Paper I, only sources with an off-axis angle < 13 arcmin were processed by the authors' X-ray data processing pipeline software, XAMIN. The catalog includes all the extended sources classified in the customary C1 and C2 classes (see Section 3.6 of Paper II) plus all point-like sources with a point source detection likelihood (DET_LH) greater than 15 (so-called non-spurious sources). This table was created by the HEASARC in February 2013 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/429/1652">CDS catalog J/MNRAS/429/1652</a> file 2xlssd.dat. This is a service provided by NASA HEASARC .
XMM-Newton Large-Scale Structure Optical Counterparts and Redshifts
Short Name:
XMMLSSCLAS
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
The XMM-Large Scale Structure (XMM-LSS) survey, covering an area of 11.1 square degrees, contains more than 6,000 X-ray point-like sources detected with the XMM-Newton Observatory to a flux of 3 x 10<sup>-15</sup> erg/s/cm<sup>2</sup> in the 0.5-2.0 keV band. The vast majority of these sources have optical (CFHTLS: Canada France Hawaii Telescope Legacy Survey), infrared (SWIRE: Spitzer Wide-area InfraRed Extragalactic legacy survey) InfraRed Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS), near-infrared (UKIDSS: UKIRT Infrared Deep Sky Survey) and/or ultraviolet (GALEX: Galaxy Evolution Explorer) counterparts. The authors wished to investigate the environmental properties of the different types of the XMM-LSS X-ray sources by defining their environment using the i'-band CFHTLS W1 catalog of optical galaxies to a magnitude limit of 23.5 magnitudes. They have classified 4,435 X-ray selected sources on the basis of their spectra, spectral energy distributions (SEDs), and X-ray luminosities, and estimated their photometric redshifts, which have a 4-11 band photometry with an accuracy of sigma[Delta<sub>z</sub>/(1+z<sub>sp</sub>)] = 0.076, with 22.6% outliers for i' < 26 mag. The authors estimated the local overdensities of 777 X-ray sources that have spectro-z or photo-z calculated by using more than seven bands (accuracy of sigma[(Delta<sub>z</sub>/(1+z<sub>sp</sub>)] = 0.061, with 13.8% outliers) within the volume-limited region defined by 0.1 <= z <= 0.85 and -23.5 < M_i'_ < -20. Although X-ray sources may be found in variety of environments, a high fraction (~55-60%), as verified by comparing with the random expectations, reside in overdense regions. The galaxy overdensities within which X-ray sources reside show a positive recent redshift evolution (at least for the range studied; z <~ 0.85). The authors also find that X-ray selected galaxies, when compared to AGN, inhabit significantly higher galaxy overdensities, although their spatial extent appear to be smaller than that of AGN. Hard AGN (harness ratios HR >= -0.2) are located in more overdense regions than soft AGN (HR < -0.2), which is clearly seen in both redshift ranges, although it appears to be stronger in the higher redshift range (0.55 < z < 0.85). Furthermore, the galaxy overdensities (with delta > 1.5, where delta is defined in equation (3) of the reference paper) within which soft AGN are embedded appear to evolve more rapidly compared to the corresponding overdensities around hard AGN. This table contains the spectroscopic and/or photometric redshifts for 4,206 X-ray selected sources in the XMM-LSS field which have optical counterparts and have been classified by the authors. This table was created by the HEASARC in September 2013 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/557/A81">CDS Catalog J/A+A/557/A81</a> file table2.dat This is a service provided by NASA HEASARC .
