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17651. XMM serendipitous survey AXIS X-ray source counts
ID:
ivo://CDS.VizieR/J/A+A/469/27
Title:
XMM serendipitous survey AXIS X-ray source counts
Short Name:
J/A+A/469/27
Date:
21 Oct 2021
Publisher:
CDS
Description:
Recent results have revised upwards the total X-ray background (XRB) intensity below 10keV, therefore an accurate determination of the source counts is needed. There are also contradictory results on the clustering of X-ray selected sources. We have studied the X-ray source counts in four energy bands: soft (0.5-2keV), hard (2-10keV), XID (0.5-4.5keV) and ultra-hard (4.5-7.5keV) in order to evaluate the contribution of sources at different fluxes to the X-ray background. We have also studied the angular clustering of X-ray sources in those bands. AXIS (An XMM International Survey) is a survey of 36 high Galactic latitude XMM observations covering 4.8deg^2^ in the Northern sky and containing 1433 serendipitous X-ray sources detected with 5-sigma significance. This survey has similar depth to the XMM catalogues and therefore serves as a pathfinder to explore their possibilities. We have combined this survey with shallower and deeper surveys, and fitted the source counts with a Maximum Likelihood technique. Using only AXIS sources we have studied the angular correlation using a novel robust technique. Our source counts results are compatible with most previous samples in the soft, XID, ultra-hard and hard bands. We have improved on previous results in the hard band. The fractions of the XRB resolved in the surveys used in this work are 87%, 85%, 60% and 25% in the soft, hard, XID and ultra-hard bands, respectively. Extrapolation of our source counts to zero flux is not sufficient to saturate the XRB intensity. Only galaxies and/or absorbed AGN could contribute the remaining unresolved XRB intensity. Our results are compatible, within the errors, with recent revisions of the XRB intensity in the soft and hard bands. The maximum fractional contribution to the XRB comes from fluxes within about a decade of the break in the source counts (~10^-14^cgs), reaching ~50% of the total in the soft and hard bands. Angular clustering (widely distributed over the sky and not confined to a few deep fields) is detected at 99-99.9% significance in the soft and XID bands, with no detection in the hard and ultra-hard band (probably due to the smaller number of sources). We cannot confirm the detection of significantly stronger clustering in the hard-spectrum hard sources. Medium depth surveys such as AXIS are essential to determine the evolution of the X-ray emission in the Universe below 10keV.
17652. XMM sources in Blanco 1
ID:
ivo://CDS.VizieR/J/A+A/421/175
Title:
XMM sources in Blanco 1
Short Name:
J/A+A/421/175
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an X-ray study of the high metallicity young open cluster Blanco 1 based on XMM-Newton data. X-ray spectroscopy of cluster members is presented for the first time as well as new X-ray distribution functions of late-type stars. We detected all known dF and dG stars in the EPIC field and 80% and 90% of dK and dM stars, respectively. The X-ray spectral analysis of the X-ray brightest cluster stars and X-ray color analysis of a larger sample show that a model with two temperatures (at about 0.3 and 1keV) explains the quiescent activity phase spectra. We discuss also the nature of unidentified X-ray sources in the observed region and their X-ray spectral properties.
17653. XMM sources in IC 1805
ID:
ivo://CDS.VizieR/J/A+A/594/A82
Title:
XMM sources in IC 1805
Short Name:
J/A+A/594/A82
Date:
21 Oct 2021
Publisher:
CDS
Description:
Very young open clusters are ideal places to study the X-ray properties of a homogeneous population of early-type stars. In this respect, the IC 1805 open cluster is very interesting as it hosts the O4 If+ star HD 15570 thought to be in an evolutionary stage intermediate between a normal O-star and a Wolf-Rayet star. Such a star could provide a test for theoretical models aiming at explaining the empirical scaling relation between the X-ray and bolometric luminosities of O-type stars. We have observed IC 1805 with XMM-Newton and further collected optical spectroscopy of some of the O-star members of the cluster. The optical spectra allow us to revisit the orbital solutions of BD+60 497 and HD 15558, and provide the first evidence of binarity for BD+60 498. X-ray emission from colliding winds does not appear to play an important role among the O-stars of IC 1805. Notably, the X-ray fluxes do not vary significantly between archival X-ray observations and our XMM-Newton pointing. The very fast rotator BD+60 513, and to a lesser extent the O4 If+ star HD 15570 appear somewhat underluminous. Whilst the underluminosity of HD 15570 is only marginally significant, its amplitude is found to be compatible with theoretical expectations based on its stellar and wind properties. A number of other X-ray sources are detected in the field, and the brightest objects, many of which are likely low-mass pre-main sequence stars, are analyzed in detail.
17654. XMM sources in M83 (NGC5236)
ID:
ivo://CDS.VizieR/J/A+A/553/A7
Title:
XMM sources in M83 (NGC5236)
Short Name:
J/A+A/553/A7
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results obtained from the analysis of three XMM-Newton observations of M83. The aims of the paper are studying the X-ray source populations in M83 and calculating the X-ray luminosity functions of X-ray binaries for different regions of the galaxy. We detected 189 sources in the XMM-Newton field of view in the energy range of 0.2-12keV. We constrained their nature by means of spectral analysis, hardness ratios, studies of the X-ray variability, and cross-correlations with catalogues in X-ray, optical, infrared, and radio wavelengths.
17655. XMM sources in NGC1512/1510
ID:
ivo://CDS.VizieR/J/A+A/566/A115
Title:
XMM sources in NGC1512/1510
Short Name:
J/A+A/566/A115
Date:
21 Oct 2021
Publisher:
CDS
Description:
The galaxy NGC1512 is interacting with the smaller galaxy NGC1510 and shows a peculiar morphology, characterised by two extended arms immersed in an HI disc whose size is about four times larger than the optical diameter of NGC1512. For the first time we performed a deep X-ray observation of the galaxies NGC1512 and NGC1510 with XMM-Newton to gain information on the population of X-ray sources and diffuse emission in a system of interacting galaxies. We identified and classified the sources detected in the XMM-Newton field of view by means of spectral analysis, hardness-ratios calculated with a Bayesian method, X-ray variability, and cross-correlations with catalogues in optical, infrared, and radio wavelengths. We also made use of archival Swift (X-ray) and Australia Telescope Compact Array (radio) data to better constrain the nature of the sources detected with XMM-Newton. We detected 106 sources in the energy range of 0.2-12keV, out of which 15 are located within the D_25_ regions of NGC1512 and NGC1510 and at least six sources coincide with the extended arms. We identified and classified six background objects and six foreground stars. We discussed the nature of a source within the D_25_ ellipse of NGC1512, whose properties indicate a quasi-stellar object or an intermediate ultra-luminous X-ray source. Taking into account the contribution of low-mass X-ray binaries and active galactic nuclei, the number of high-mass X-ray binaries detected within the D_25_ region of NGC1512 is consistent with the star formation rate obtained in previous works based on radio, infrared optical, and UV wavelengths. We detected diffuse X-ray emission from the interior region of NGC1512 with a plasma temperature of kT=0.68(0.31-0.87)keV and a 0.3-10keV X-ray luminosity of 1.3E+38erg/s, after correcting for unresolved discrete sources.
17656. XMM spectral analysis of Draco dSph
ID:
ivo://CDS.VizieR/J/ApJ/821/54
Title:
XMM spectral analysis of Draco dSph
Short Name:
J/ApJ/821/54
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the spectral analysis of an 87ks XMM-Newton observation of Draco, a nearby dwarf spheroidal galaxy. Of the approximately 35 robust X-ray source detections, we focus our attention on the brightest of these sources, for which we report X-ray and multiwavelength parameters. While most of the sources exhibit properties consistent with active galactic nuclei, few of them possess the characteristics of low-mass X-ray binaries (LMXBs) and cataclysmic variable (CVs). Our analysis places constraints on the population of X-ray sources with LX>3x10^33^erg/s in Draco, suggesting that there are no actively accreting black hole and neutron star binaries. However, we find four sources that could be quiescent state LMXBs/CVs associated with Draco. We also place constraints on the central black hole luminosity and on a dark matter decay signal around 3.5keV.
17657. XMM survey of NGC 2516
ID:
ivo://CDS.VizieR/J/A+A/450/993
Title:
XMM survey of NGC 2516
Short Name:
J/A+A/450/993
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report a deep X-ray survey of the young (~140Myr), rich open cluster NGC 2516 obtained with the EPIC camera on board the XMM-Newton satellite. By combining data from six observations, a high sensitivity, greater than a factor of 5 with respect to recent Chandra observations, has been achieved. Kaplan-Meier estimators of the cumulative X-ray luminosity distribution are built, statistically corrected for non members contaminants and compared to those of the nearly coeval Pleiades. The EPIC spectra of the X-ray brightest stars are fitted using optically thin model plasma with one or two thermal components. We detected 431 X-ray sources and 234 of them have as optical counterparts cluster stars spanning the entire NGC 2516 Main Sequence.
17658. XMM survey of soft background. III. Galactic halo
ID:
ivo://CDS.VizieR/J/ApJ/773/92
Title:
XMM survey of soft background. III. Galactic halo
Short Name:
J/ApJ/773/92
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present measurements of the Galactic halo's X-ray emission for 110 XMM-Newton sight lines selected to minimize contamination from solar wind charge exchange emission. We detect emission from few million degree gas on ~4/5 of our sight lines. The temperature is fairly uniform (median = 2.22x10^6^K, interquartile range = 0.63x10^6^K), while the emission measure and intrinsic 0.5-2.0keV surface brightness vary by over an order of magnitude (~(0.4-7)x10^-3^cm^-6^pc and ~(0.5-7)x10^-12^erg/cm2/s deg^-2^, respectively, with median detections of 1.9x10^-3^cm^-6^pc and 1.5x10^-12^erg/cm2/s deg^-2^, respectively). The high-latitude sky contains a patchy distribution of few million degree gas. This gas exhibits a general increase in emission measure toward the inner Galaxy in the southern Galactic hemisphere. However, there is no tendency for our observed emission measures to decrease with increasing Galactic latitude, contrary to what is expected for a disk-like halo morphology. The measured temperatures, brightnesses, and spatial distributions of the gas can be used to place constraints on models for the dominant heating sources of the halo. We provide some discussion of such heating sources, but defer comparisons between the observations and detailed models to a later paper.
17659. XMM survey of 12um selected galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/413/1206
Title:
XMM survey of 12um selected galaxies
Short Name:
J/MNRAS/413/1206
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an X-ray spectral analysis of 126 galaxies of the 12um galaxy sample (Rush et al. 1993, Cat. VII/157). By studying this sample at X-ray wavelengths, we aim to determine the intrinsic power, continuum shape and obscuration level in these sources. We improve upon previous works by the use of superior data in the form of higher signal-to-noise ratio spectra, finer spectral resolution and a broader bandpass from XMM-Newton. We pay particular attention to Compton thick active galactic nucleus (AGN) with the help of new spectral fitting models that we have produced, which are based on Monte Carlo simulations of X-ray radiative transfer, using both a spherical and torus geometry, and taking into account Compton scattering and iron fluorescence.
17660. 2XMM ultraluminous X-ray source candidates
ID:
ivo://CDS.VizieR/J/MNRAS/416/1844
Title:
2XMM ultraluminous X-ray source candidates
Short Name:
J/MNRAS/416/1844
Date:
21 Oct 2021
Publisher:
CDS
Description:
Ultraluminous X-ray sources (ULXs) are some of the most enigmatic X-ray bright sources known to date. It is generally accepted that they cannot host black holes as large as those associated with active galaxies, but they appear to be significantly more luminous than their better understood Galactic X-ray binary (XRB) cousins, while displaying an intriguing combination of differences and similarities with them. Through studying large, representative samples of these sources we may hope to enhance our understanding of them. To this end, we derive a large catalogue of 650 X-ray detections of 470 ULX candidates, located in 238 nearby galaxies, by cross-correlating the 2XMM Serendipitous Survey with the Third Reference Catalogue of Bright Galaxies.

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