- ID:
- ivo://CDS.VizieR/J/A+A/480/397
- Title:
- XMM observations of NGC 2808 and NGC 4372
- Short Name:
- J/A+A/480/397
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galactic globular clusters harbour binary systems that are detected as faint X-ray sources. These close binaries are thought to play an important role in the stability of the clusters by liberating energy and delaying the inevitable core collapse of globular clusters. The inventory of close binaries and their identification is therefore essential. We present XMM-Newton observations of two Galactic globular clusters: NGC 2808 and NGC 4372. We use X-ray spectral and variability analysis combined with ultra-violet observations made with the XMM-Newton optical monitor and published data from the Hubble Space Telescope to identify sources associated with the clusters. We compare the results of our observations with estimates from population synthesis models.
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- ID:
- ivo://CDS.VizieR/J/A+A/456/977
- Title:
- XMM observations of NGC 2516 stars
- Short Name:
- J/A+A/456/977
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the characteristics of the X-ray variability of stars in the cluster NGC 2516 as derived from XMM-Newton/EPIC/pn data. The X-ray variations on short (hours), medium (months), and long (years) time scales have been explored. We detected 303 distinct X-ray sources by analysing six EPIC/pn observations; 194 of them are members of the cluster. Stars of all spectral types, from the early-types to the late-M dwarfs, were detected.
- ID:
- ivo://CDS.VizieR/J/A+A/446/501
- Title:
- XMM observations of sigma Ori cluster
- Short Name:
- J/A+A/446/501
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an XMM-Newton observation of the young (~2-4Myr) cluster around the hot star sigma Orionis. In a previous paper (Sanz-Forcada et al., 2004A&A...421..715S) we presented the analysis of the RGS spectrum of the central hot star; here we discuss the results of the analysis of the full EPIC field. We have detected 175 X-ray sources, 88 of which have been identified with cluster members, including very low-mass stars down to the substellar limit. We detected eleven new possible candidate members from the 2MASS (Cat. <II/246>) catalogue.
- ID:
- ivo://CDS.VizieR/J/A+A/479/283
- Title:
- XMM observations of the Lockman Hole
- Short Name:
- J/A+A/479/283
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Lockman Hole represents the sky area of lowest Galactic line-of-sight columns density. It was observed by the XMM-Newton X-ray observatory in 18 pointings performed between April 2000 and December 2002. The total exposure time spent on the field was 1.16Ms (EPIC pn detector; EPIC MOS detector: 1.30 Ms). The effective exposure after removal of times of high particle background is 637ks (EPIC pn detector; EPIC MOS detector: 765ks). The catalogue lists positions, count rates, fluxes, hardness ratios, and partial optical classifications of 409 X-ray point sources detected in the central 0.196{deg}2 of the field down to a detection likelihood threshold of 10 (3.9sigma). The analysis was performed using the XMM-Newton SAS data analysis package version 6.0.
- ID:
- ivo://CDS.VizieR/J/ApJ/820/L28
- Title:
- XMM obs. of two regions west to {kappa} Ori
- Short Name:
- J/ApJ/820/L28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- X-rays are a powerful probe of activity in early stages of star formation. They allow us to identify young stars even after they have lost the IR signatures of circumstellar disks and provide constraints on their distance. Here, we report on XMM-Newton observations that detect 121 young stellar objects (YSOs) in two fields between L1641S and {kappa} Ori. These observations extend the Survey of Orion A with XMM and Spitzer (SOXS). The YSOs are contained in a ring of gas and dust apparent at millimeter wavelengths, and in far-IR and near-IR surveys. The X-ray luminosity function of the YSOs detected in the two fields indicates a distance of 250-280pc, much closer than the Orion A cloud and similar to distance estimates of {kappa} Ori. We propose that the ring is a 5-8pc diameter shell that has been swept up by {kappa} Ori. This ring contains several groups of stars detected by Spitzer and WISE including one surrounding the Herbig Ae/Be stars V1818 Ori. In this interpretation, the {kappa} Ori ring is one of several shells swept up by massive stars within the Orion Eridanus Superbubble and is unrelated to the southern portion of OrionA/L1641S.
1076. XMMOMCDFS catalogue
- ID:
- ivo://CDS.VizieR/J/A+A/574/A49
- Title:
- XMMOMCDFS catalogue
- Short Name:
- J/A+A/574/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The XMM-Newton X-ray observatory has performed repeated observations of the CDFS in 33 epochs (2001-2010) through the XMM-CDFS Deep Survey. During the X-ray observations, XMM-OM targeted the central 17x17arcmin^2^ region of the X-ray field of view, providing simultaneous optical/UV coverage of the CDFS. The resulting set of data can be taken into account to build an XMM-OM catalogue of the CDFS, filling the UV spectral coverage between the optical surveys and GALEX observations. We present the UV catalogue of the XMM-CDFS Deep Survey. Its main purpose is to provide complementary UV average photometric measurements of known optical/UV sources in the CDFS, taking advantage of the unique characteristics of the survey. The data reduction is intended also to improve the standard source detection on individual observations, by cataloguing faint sources through the stacking of their exposure images. We reprocessed the XMM-OM data of the survey and we stacked the exposures from consecutive observations using the standard SAS tools to process the data obtained during single observations. Average measurements of detections with SAS good quality flags from individual observations and from stacked images have been joined to compile the catalogue. Sources have been validated through the cross-identification within the EIS and COMBO-17 surveys. Photometric data of 1129 CDFS sources are provided into the catalogue, and optical/UV/X-ray photometric and spectroscopic information from other surveys are also included. The stacking extends the detection limits by ~1 mag in the three UV bands, contributing 30% of the catalogued UV sources. The comparison with the available measurements in similar spectral bands confirms the validity of the XMM-OM calibration. The combined COMBO-17/X-ray classification of the "intermediate" sources (e.g. optically diluted and/or X-ray absorbed AGN) is also discussed.
- ID:
- ivo://CDS.VizieR/J/A+A/468/379
- Title:
- XMM Optical Monitor Survey of TMC
- Short Name:
- J/A+A/468/379
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Optical Monitor (OM) on-board XMM-Newton obtained optical/ultraviolet data for the XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST), simultaneously with the X-ray detectors. With the XEST OM data, we study the optical and ultraviolet properties of TMC members, and to perform correlative studies between the X-ray and OM light curves. In particular, we aim to determine whether accretion plays a significant role in the optical/ultraviolet and X-ray emissions. The Neupert effect in stellar flares is also investigated. Coordinates, average count rates and magnitudes were extracted from OM images, together with light curves with low time resolution (a few kiloseconds). For a few sources, OM FAST mode data were also available, and we extracted OM light curves with high time resolution. The OM data were correlated with Two Micron All Sky Survey (2MASS) data and with the XEST catalogue in the X-rays. The XEST OM catalogue contains 2,148 entries of which 1,893 have 2MASS counterparts. However, only 98 entries have X-ray counterparts, of which 51 are known TMC members and 12 additional are TMC candidates. The OM data indicate that accreting stars are statistically brighter in the U band than non-accreting stars after correction for extinction, and have U-band excesses, most likely due to accretion. The OM emission of accreting stars is variable, probably due to accretion spots, but it does not correlate with the X-ray light curve, suggesting that accretion does not contribute significantly to the X-ray emission of most accreting stars. In some cases, flares were detected in both X-ray and OM light curves and followed a Neupert effect pattern, in which the optical/ultraviolet emission precedes the X-ray emission of a flare, whereas the X-ray flux is proportional to the integral of the optical flux.
- ID:
- ivo://CDS.VizieR/J/A+A/594/A32
- Title:
- 3XMM/SDSS Stripe 82 Galaxy Cluster Survey. I.
- Short Name:
- J/A+A/594/A32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a galaxy cluster survey based on XMM-Newton observations that are located in Stripe 82 of the Sloan Digital Sky Survey (SDSS). The survey covers an area of 11.25deg^2^. The X-ray cluster candidates were selected as serendipitously extended detected sources from the third XMM-Newton serendipitous source catalogue (3XMM-DR5). A cross-correlation of the candidate list that comprises 94 objects with recently published X-ray and optically selected cluster catalogues provided optical confirmations and redshift estimates for about half of the candidate sample. We present a catalogue of X-ray cluster candidates previously known in X-ray and/or optical bands from the matched catalogues or NED. The catalogue consists of 54 systems with redshift measurements in the range of 0.05-1.19 with a median of 0.36. Of these, 45 clusters have spectroscopic confirmations as stated in the matched catalogues. We spectroscopically confirmed another 6 clusters from the available spectroscopic redshifts in the SDSS-DR12. The cluster catalogue includes 17 newly X-ray discovered clusters, while the remainder were detected in previous XMM-Newton and/or ROSAT cluster surveys. Based on the available redshifts and fluxes given in the 3XMM-DR5 catalogue, we estimated the X-ray luminosities and masses for the cluster sample. We also present the list of the remaining X-ray cluster candidates (40 objects) that have no redshift information yet in the literature. Of these candidates, 25 sources are considered as distant cluster candidates beyond a redshift of 0.6. We also searched for galaxy cluster mergers in our cluster sample and found two strong candidates for newly discovered cluster mergers at redshifts of 0.11 and 0.26. The X-ray and optical properties of these systems are presented.
- 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.
1080. 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.
