- ID:
- ivo://nasa.heasarc/kaporixmm
- Title:
- Kappa Orionis XMM-Newton X-Ray Point Source Catalog
- Short Name:
- KAPORIXMM
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- X-rays are a powerful probe of activity in the 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, the authors report on XMM-Newton observations that detected 121 young stellar objects (YSOs) in two fields between the filamentary dark cloud complex Lynds 1641S and the star 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 250-280 pc, much closer than the Orion A cloud and similar to the distance estimates for Kappa Ori. The authors propose that the ring is a 5-8 pc 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 star 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 Orion A/L 1641S. The XMM-Newton observations consist of two fields, north (Field N = KN) and south (Field S = KS), and were obtained in 2015 March 10 and 15 using EPIC as the primary instrument. Table 1 in the reference paper shows the details of the exposures, each one with a duration of about 50 ks and taken with the Medium filter. The authors used SAS version 14.0 to reduce the observation data files (ODFs) and to obtain calibrated lists of events for the MOS and pn instruments. They filtered the events in the 0.3-0.8 keV energy band and used only events with FLAG = 0 and PATTERN < 12 as prescribed by the SAS manual. With SAS, the authors obtained exposure maps in the 0.3-8.0 keV band and performed source detection with a code based on wavelet convolution that operated simultaneously on MOS and pn data. They used a threshold of significance of 4.5 sigma of the local background to discriminate real sources from spurious background fluctuations. However, they added few sources to the final list with significance S in 4.0 < S < 4.5 for the cases of positional match with objects in SIMBAD or PPMX catalogs. The final list was also checked for spurious sources that could appear at the border of the CCDs. In sum, the authors detected 238 X-ray sources with significance > 4 sigma of the local background; 104 sources are in KN and 134 in KS. The authors cross-correlated the positions of the X-ray sources with the coordinates of the IR catalog of Megeath et al. (2012, AJ, 144, 192). This IR catalog is the result of a survey of Orion with Spitzer that produced a classification of protostars and stars with disks. Of the 238 X-ray sources, 191 are identified within 8 arcseconds of one of 206 IR objects, 99 sources in KS, 92 sources in KN. Some X-ray sources were multiple matches within 8 arcsec of IR objects. For these cases, the authors assigned the most likely counterparts based on IR photometry and visual inspection of X-rays and IR images. However, nine X-ray sources were left associated with two or three IR objects. Among the IR matches, the authors found 15 stars with disks in KN and 35 in KS with X-ray detection. One protostar in KN and three in KS were detected in X-rays. The authors used X-ray detection of sources without IR excess as criteria to identify disk-less stars (hereafter Class III stars). They classified as Class III stars those IR objects with X-ray detections, with [4.5um]-[8.0um] colors < 0.3 mag and brighter than [4.5um] magnitude < 14. At the distance of the ONC (400 pc), the [4.5um] magnitude ~ 14 threshold at an age of 4-5 Myrs roughly identifies M3-M4 spectral types and masses around 0.3 solar masses. With this selection scheme, the authors identified 48 objects in KN and 19 in KS as Class III candidates. This table was created by the HEASARC in August 2016 based on the electronic version of Table 2 from the reference paper which was obtained from the CDS (their catalog J/ApJ/820/L28 file table2.dat). This is a service provided by NASA HEASARC .
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Search Results
- ID:
- ivo://nasa.heasarc/lamorixmm
- Title:
- Lambda Orionis Cluster XMM-Newton X-Ray Point Source Catalog
- Short Name:
- LAMORIXMM
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors studied the X-ray properties of the young (~1-8M yr) open cluster around the hot (O8 III) star Lambda Ori and compared them with those of the similarly-aged Sigma Ori cluster in order to investigate the possible effects of the different ambient environments. They analyzed an XMM-Newton observation of the cluster using EPIC imaging and low-resolution spectral data. They studied the variability of the detected sources, and performed a spectral analysis of the brightest sources in the field using multi-temperature models. The authors detected 167 X-ray sources above a 5-sigma detection threshold the properties of which are listed in this table, of which 58 are identified with known cluster members and candidates, from massive stars down to low-mass stars with spectral types of ~ M5.5. Another 23 sources were identified with new possible photometric candidates. Late-type stars have a median log L<sub>X</sub>/L<sub>bol</sub> ~ -3.3, close to the saturation limit. Variability was observed in ~ 35% of late-type members or candidates, including six flaring sources. The emission from the central hot star Lambda Ori is dominated by plasma at 0.2 - 0.3 keV, with a weaker component at 0.7 keV, consistent with a wind origin. The coronae of late-type stars can be described by two plasma components with temperatures T<sub>1</sub> ~ 0.3-0.8 keV and T<sub>2</sub> ~ 0.8-3 keV, and subsolar abundances Z ~ 0.1-0.3 Z<sub>sun</sub>, similar to what is found in other star-forming regions and associations. No significant difference was observed between stars with and without circumstellar discs, although the smallness of the sample of stars with discs and accretion does not definitive conclusions to be drawn. The authors concluded that the X-ray properties of Lambda Ori late-type stars are comparable to those of the coeval Sigma Ori cluster, suggesting that stellar activity in Lambda Ori has not been significantly affected by the different ambient environment. The lambda Ori cluster was observed by XMM-Newton from 20:46 UT on September 28, 2006 to 12:23 UT on September 29, 2006 (Obs. ID 0402050101), for a total duration of 56ks, using both the EPIC MOS and PN cameras and the RGS instruments. The EPIC cameras were operated in full frame mode with the thick filter. This table was created by the HEASARC in November 2011 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/530/A150">CDS Catalog J/A+A/530/A150</a> files tablea1.dat ('X-ray sources detected in the Lambda Ori Cluster'), table1,dat ('X-ray and optical properties of sources identified with known cluster members and candidates') and table2.dat ('X-ray sources identified with possible new cluster candidates'). It does not include the objects listed in tablea2.dat ('3-sigma upper limits and optical properties of undetected cluster members and candidates'). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/lockmanoir
- Title:
- Lockman Hole AGN Optical and Infrared Properties Catalog
- Short Name:
- LOCKMANOIR
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the observed-frame optical, near-infrared, and mid-infrared properties of X-ray-selected active galactic nuclei (AGN) in the Lockman Hole. Using a likelihood ratio method on optical, near-infrared or mid-infrared catalogs, the authors assigned counterparts to 401 out of the 409 X-ray sources of the XMM-Newton catalog (Brunner et al. 2008, A&A, 479, 283). Accurate photometry was collected for all the sources from U to 24 microns. The authors used X-ray and optical criteria to remove any normal galaxies, galactic stars, or X-ray clusters among them and studied the multi-wavelength properties of the remaining 377 AGN in their paper. They used a mid-IR colour-colour selection to understand the AGN contribution to the optical and infrared emission. Using this selection, they identified different behaviours of AGN-dominated and host-dominated sources in X-ray-optical-infrared color-color diagrams. More specifically, the AGN-dominated sources show a clear trend in the f<sub>x</sub>/f<sub>RC</sub> vs. R<sub>C</sub> - K and f<sub>24um</sub>/f<sub>RC</sub> vs. R<sub>C</sub> - K diagrams, while the hosts follow the behaviour of non-X-ray detected galaxies. In the optical-near-infrared color-magnitude diagram, the known trend of redder objects to be more obscured in X-rays is seen to be stronger for AGN-dominated than for host-dominated systems. This is an indication that the trend is more related to the AGN, which contaminate the overall colors, than to any evolutionary effects, the authors believe. Finally, the authors find that a significant fraction (~30%) of the reddest AGN are not obscured in X-rays. The X-ray observations of the Lockman Hole took place between April 2000 and December 2002 with XMM-Newton. The optical observations of the Lockman Hole were conducted with the Large Binocular Telescope (U, B, V bands) and the Subaru Telescope (R<sub>C</sub>, I<sub>C</sub>, z' bands). The LBT observations were taken from February 2007 to March 2009. The R<sub>C</sub>, I<sub>C</sub>, and z' bands have been observed with the Suprime-Cam of the Subaru telescope between November 2001 and April 2002. This table contains the properties of the counterparts to all 409 X-ray sources listed in the Lockman Hole XMM-Newton source catalog of Brunner et al. (2008, A&A, 479, 283), including the 377 AGN and also the 32 objects classified as Galactic stars, galaxy clusters or galaxies. For 8 (2%) of the 409 X-ray sources no optical or IR counterparts were found. These 8 objects are listed in this table with null positional values. This table was created by the HEASARC in January 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/529/A135">CDS Catalog J/A+A/529/A135</a> file table2.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/lockmanxmm
- Title:
- Lockman Hole Field XMM-Newton X-Ray Point Source Catalog
- Short Name:
- LOCKMANXMM
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the results of a detailed X-ray spectral analysis of a sample of 123 X-ray sources detected with XMM-Newton in the Lockman Hole field. This is the deepest observation carried out as yet with XMM-Newton with more that 600 ks of good EPIC-pn data.There are spectra with good signal to noise (>500 source counts) for all objects down to 0.2 - 12 keV fluxes of 5 x 10<sup>-15</sup> erg/cm<sup>2</sup>/s (the flux limit is 6 x 10<sup>-16</sup> erg/cm<sup>2</sup>/s in the 0.5 - 2.0 and 2 - 10 keV bands). At the time of the analysis, the authors had optical spectroscopic identifications for 60% of the sources, 46 being optical type-1 AGN and 28 optical type-2 AGN. Using a single power law model, their sources' average spectral slope hardens at faint 0.5 - 2 keV fluxes but not at faint 2 - 10 keV fluxes. This table was created by the HEASARC in June 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/444/79">CDS Catalog J/A+A/444/79</a>, file table8.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/lockmanxm2
- Title:
- Lockman Hole XMM-Newton X-Ray Point Source Catalog
- Short Name:
- LOCKMANXM2
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- 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 1.16 Ms (EPIC pn detector; EPIC MOS detector: 1.30 Ms). The effective exposure after removal of times of high particle background is 637 ks (EPIC pn detector; EPIC MOS detector: 765 ks). The catalog lists positions, count rates, fluxes, hardness ratios, and partial optical classifications of 409 X-ray point sources detected in the central 0.196 square degrees of the field down to a detection likelihood threshold in the full energy band of 10 (3.9 sigma), up to 4 of which may be spurious according to the authors' Monte Carlo simulations. The analysis was performed using the XMM-Newton SAS data analysis package version 6.0. This table was created by the HEASARC in May 2008 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/479/283">CDS Catalog J/A+A/479/283</a> file table3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/lupus3xmm
- Title:
- Lupus 3 SFR XMM-Newton X-Ray Point Source Catalog
- Short Name:
- LUPUS3XMM
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the analysis results of an XMM-Newton observation of the Lupus 3 region that contains a high proportion of young low-mass (< 0.3 solar masses) T Tauri stars in the Lupus star-forming complex. The observation had a ~22-ks effective exposure in the pn and MOS cameras. The detection of X-ray sources in 0.5 - 4.5 keV images of the Lupus 3 core was performed using the standard source detection method in the XMM-Newton Science Analysis Software (SAS). 102 candidate X-ray sources were detected with a likelihood threshold of >= 12 (corresponding to 4.4 sigma in Gaussian statistics) in the 30-arcmin diameter field-of-view of the EPIC cameras, of which 25 have visible or near-IR counterparts within the adopted 4" correlation radius for each X-ray source that were known to be pre-main sequence stars. Their X-ray luminosities range from 3 x 10<sup>28</sup> to 3 x 10<sup>30</sup> erg/s. This table gives the list of X-ray sources detected in the core of the Lupus 3 region with the EPIC camera on-board XMM-Newton, except that the X-ray source associated with the star HR 6000 (the nominal target of the XMM-Newton observation of the original PI) has been excluded. Additional information on the optical and IR counterparts of 25 of the X-ray sources, and on the X-ray spectra, is available in the reference paper. This table was created by the HEASARC in Match 2007 based on CDS table J/A+A/454/595 file table6.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/l1641ioxmm
- Title:
- Lynds 1641 and iota Ori Region XMM-Newton X-Ray Point Source Catalog
- Short Name:
- L1641IOXMM
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains results from an XMM-Newton and Spitzer survey of the part of the Orion A cloud south of the Orion Nebula, the 'Survey of Orion A with XMM-Newton and Spitzer (SOXS)'. The goal of SOXS is to detect the relatively bright X-ray sources in the Orion A cloud and complete the census of more evolved YSOs in this region. These stars represent a sample of cloud members chosen with minimal a priori bias toward their IR properties. This XMM-Newton survey includes the Lynds 1641 (L1641) dark cloud, a region of the Orion A cloud with very few massive stars and hence a relatively low ambient UV flux, and the region around the O9 III star iota Orionis. In addition to proprietary data, the authors used archival XMM data of the Orion Nebula Cluster (ONC) to extend their analysis to a major fraction of the Orion A cloud. They have detected 1060 X-ray sources with more than 4.5-sigma significance in L1641 and the iota Ori region. About 94% of the sources have Two Micron All Sky Survey (2MASS) and Spitzer counterparts, 204 and 23 being Class II and Class I or protostar objects, respectively. In addition, the authors have identified 489 X-ray sources as counterparts to Class III candidates, given they are bright in X-rays and appear as normal photospheres at mid-IR wavelengths. The remaining 205 X-ray sources are likely distant active galactic nuclei (AGN) or other galactic sources not related to Orion A. The authors find that Class III candidates appear more concentrated in two main clusters in L1641. The first cluster of Class III stars is found toward the northern part of L1641, concentrated around iota Ori. The stars in this cluster are more evolved than those in the Orion Nebula. The authors estimate a distance of 300-320 pc for this cluster showing that it is in the foreground of the Orion A cloud. Another cluster rich in Class III stars is located in L1641 South and appears to be a slightly older cluster embedded in the Orion A cloud. Furthermore, other evolved Class III stars are found north of the ONC toward NGC 1977. The SOXS survey is composed of seven specifically proposed ~ 50 ks XMM-Newton fields, south of the ONC, to which the authors added four archival fields in the same region. The archival fields are centered on iota Orionis, V380 Ori, and V883 Ori, respectively (see Fig. 1 and Table 1 of the reference paper for more details of the X-ray observations). This HEASARC table contains the contents of Table 2 (1060 X-ray detected sources in the fields S1 - S10 listed in Table 1 of the reference paper), Table 3 (best-fit spectral parameters for the 232 brightest of these X-ray sources) and Table 4 (list of 1041 IR counterparts to the X-ray sources) from the reference paper. Some X-ray sources have no identified counterparts (16 of them in fact lie outside of the FOV of the Spitzer observations), most have a single counterpart, and a small number have 2 or even 3 IR counterparts within the 5 arcseconds matching radius used. For X-ray sources with more than 1 IR counterpart, we have added entries for the additional counterparts (71 in total), repeating the X-ray information in such cases. Thus, this HEASARC table contains 1131 (1060 + 71) entries corresponding to the 1060 X-ray source detections. To make its contents easier to visualize, the HEASARC has added a a parameter ir_match which lists the counterpart number for the entry: If there is no identified IR counterpart, ir_match is set to 0, for the first listed IR counterpart to 1, for the second and third, to 2 and 3, respectively. Thus, if the user wants to reduce the table back to a pure list of X-ray sources and their primary IR counterparts, they should search the table selecting ir_match < 2. This table was created by the HEASARC in August 2013 based on the electronic versions of Tables 2 and 3 from the original reference paper (2013ApJ...768...99P) and Table 4 from the erratum (2013ApJ...773...80P), which were all obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/maranoxmm
- Title:
- Marano Field XMM-Newton X-Ray Source Optical Counterparts
- Short Name:
- MARANOXMM
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains some of the results from a medium deep XMM-Newton survey of the Marano Field and optical follow-up observations. The mosaicked XMM-Newton pointings in this optical quasar survey field cover 0.6 deg<sup>2</sup> with a total of 120 ks good observation time. 328 X-ray sources were detected in total with detection likelihoods ML >= 5. The X-ray fluxes are in the range f<sub>X</sub> = (0.16 - 54) x 10<sup>-14</sup> erg cm<sup>-2</sup> s<sup>-1</sup> (0.2 - 10 keV). The turnover flux of this sample is f<sub>X</sub> ~ 5 x 10<sup>-15</sup> erg/cm<sup>2</sup>/s in this same energy band. With VLT FORS1 and FORS2 spectroscopy 96 new X-ray counterparts have been classified. The central 0.28 deg<sup>2</sup> region, where detailed optical follow-up observations were performed, contains ~ 170 X-ray sources (detection likelihood ML > 10), out of which 48 had already been detected by ROSAT. In this region 23 out of 29 optically selected quasars have been recovered. With a total of 110 classifications in their core sample, the authors have reached a completeness of ~65%. About one-third of the XMM-Newton sources are classified as type II AGN with redshifts mostly below 1.0. Furthermore, five high redshift type II AGN (2.2 <= z <= 2.8) have been detected. This table contains the list of the 195 optical counterparts for 172 of the XMM-Newton X-ray sources given in Table 8 of the reference paper. It does not contain the full list of 328 X-ray sources given in Table A1 of the reference paper, nor the lists of marginal X-ray sources given in Appendix B of the reference paper. This table was created by the HEASARC in May 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/466/41">CDS catalog J/A+A/466/41</a> file table8.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/m33deepxmm
- Title:
- M 33 Deep XMM-Newton Survey X-Ray Source Catalog
- Short Name:
- M33DEEPXMM
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have obtained a deep 8-field XMM-Newton mosaic of M33 covering the galaxy out to the D<sub>25</sub> isophote and beyond to a limiting 0.2-4.5 keV unabsorbed flux of 5 x 10<sup>-16</sup> erg cm<sup>-2</sup> s<sup>-1</sup> (L > 4 x 10<sup>34</sup> erg s<sup>-1</sup> at the 817 kpc distance of M33). These data allow complete coverage of the galaxy with high sensitivity to soft sources such as diffuse hot gas and supernova remnants (SNRs). In the reference paper, the authors describe the methods they used to identify and characterize 1296 point sources in the 8 fields. They compare their resulting source catalog to the literature, note variable sources, construct hardness ratios, classify soft sources, analyze the source density profile, and measure the X-ray luminosity function (XLF). As a result of the large effective area of XMM-Newton below 1 keV, the survey contains many new soft X-ray sources. The radial source density profile and XLF for the sources suggest that only ~15% of the 391 bright sources with L > 3.6 x 10<sup>35</sup> erg s<sup>-1</sup> are likely to be associated with M33, and more than a third of these are known SNRs. The log(N)-log(S) distribution, when corrected for background contamination, is a relatively flat power law with a differential index of 1.5, which suggests that many of the other M33 sources may be high-mass X-ray binaries. Finally, the authors note the discovery of an interesting new transient X-ray source, which they are unable to classify. The list of XMM-Newton observations used for this survey is given in Table 1 of the reference paper. The data reduction and source detection techniques are described in Section 3 of this same reference. The unabsorbed energy conversion factors (ECF) values for different energy bands and instruments that were used in this paper are as follows (the units are 10<sup>11</sup> counts cm<sup>2</sup> erg<sup>-1</sup>): <pre> HEASARC Energy Band MOS1 MOS2 PN band prefix (keV) Med Filter Med Filter Thin Filter sb0_ 0.2-0.5 0.5009 0.4974 2.7709 sb1_ 0.5-1.0 1.2736 1.2808 6.006 mb_ 1.0-2.0 1.8664 1.8681 5.4819 hb_ 2.0-4.5 0.7266 0.7307 1.9276 fb_ 0.2-4.5 </pre> This table was created by the HEASARC in July 2015 based on an electronic version of Table 3 of the reference paper, the list of XMM-Newton X-ray point sources detected in a deep 8-field mosaic of M33, which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/m31deepxmm
- Title:
- M 31 Deep XMM-Newton Survey X-Ray Source Catalog
- Short Name:
- M31DEEPXMM
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The largest Local Group spiral galaxy, M 31, has been completely imaged for the first time, with an obtained luminosity lower limit ~10<sup>35</sup>erg/s in the 0.2 - 4.5 keV band. This XMM-Newton EPIC survey combines archival observations along the major axis, from June 2000 to July 2004, with observations taken between June 2006 and February 2008 that cover the remainder of the D<sub>25</sub> ellipse. The main goal of the present paper was to study the X-ray source populations of M31. An X-ray catalog of 1897 sources was created ('the XMM LP-total catalog'), with 914 sources detected for the first time. Source classification and identification were based on X-ray hardness ratios, spatial extents of the sources, and cross correlation with catalogs in the X-ray, optical, infrared and radio wavelengths. The authors also analysed the long-term variability of the X-ray sources and this variability allowed them to distinguish between X-ray binaries and active galactic nuclei (AGN). Furthermore, supernova remnant classifications of previous studies that did not use long-term variability as a classification criterion could be validated. Including previous Chandra and ROSAT observations in the long-term variability study allowed the authors to detect additional transient or at least highly variable sources, which are good candidate X-ray binaries. Fourteen of the 30 supersoft source (SSS) candidates represent supersoft emission of optical novae. Many of the 25 supernova remnants (SNRs) and 31 SNR candidates lie within the 10 kpc dust ring and other star-forming regions in M 31. This connection between SNRs and star-forming regions implies that most of the remnants originate in type II supernovae. The brightest sources in X-rays in M 31 belong to the class of X-ray binaries (XRBs). Ten low-mass XRBs (LMXBs) and 26 LMXB candidates were identified based on their temporal variability. In addition, 36 LMXBs and 17 LMXB candidates were identified owing to correlations with globular clusters and globular cluster candidates. From optical and X-ray colour-colour diagrams, possible high-mass XRB (HMXB) candidates were selected. Two of these candidates have an X-ray spectrum as expected for an HMXB containing a neutron star primary. While this survey has greatly improved our understanding of the X-ray source populations in M 31, at this point 65% of the sources can still only be classified as "hard" sources; i.e. it is not possible to decide whether these sources are X-ray binaries or Crab-like supernova remnants in M 31 or X-ray sources in the background. Deeper observations in X-ray and at other wavelengths would help to classify these sources. This table was created by the HEASARC in October 2011 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/534/A55">CDS Catalog J/A+A/534/A55</a> files table5.dat and table8.dat. This is a service provided by NASA HEASARC .
