- ID:
- ivo://nasa.heasarc/m51cxo2
- Title:
- M 51 Deep Chandra ACIS X-Ray Point Source Catalog
- Short Name:
- M51CXO2
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors obtained a deep X-ray image of the nearby galaxy M 51 using the Chandra X-Ray Observatory. Here the catalog of X-ray sources detected in these observations is presented, while an overview of the properties of the point-source population is provided in the reference paper. The authors find 298 sources within the D<sub>25</sub> radii (the apparent major isophotal galactic radii measured at or reduced to the surface brightness level mu<sub>B</sub> = 25.0 B-mag per square arcsecond) of NGC 5194 and NGC 5195, of which 20% are variable, a dozen are classical transients, and another half dozen are transient-like sources. The typical number of active ultraluminous X-ray sources in any given observation is ~5, and only two of those sources persist in an ultraluminous state over the 12 years of observations. Given reasonable assumptions about the supernova remnant population, the luminosity function is well described by a power law with an index between 1.55 and 1.7, only slightly shallower than that found for populations dominated by high-mass X-ray binaries (HMXBs), which suggests that the binary population in NGC 5194 is also dominated by HMXBs. The luminosity function of NGC 5195 is more consistent with a low-mass X-ray binary dominated population. This deep study of M51 is composed of 107 ks of archival Chandra observations, to which the authors added another 745 ks of observations. The Chandra ObsIDs and parameters of all of the observations used in this study (which span from June 2000 to October 2012) are given in Table 2 of the reference paper. All of the observations were made with the ACIS-S array. The authors used the ACIS Extract software package (AE) to perform the photometry. For each source, AE extracted a source region whose size and shape were based on the local PSF, and a background region whose size and shape were based on the size of the local PSF and the location of nearby sources. Source properties were then calculated in a standard manner. Of particular importance in this analysis is the prob_no_source parameter, which is the probability that one could measure the observed count rate in the absence of a source. The authors took a source to be significant only if this parameter was < 5 x 10<sup>-6</sup>. At this probability threshold, one would expect a single spurious source per field, or roughly 1.5 spurious sources within the D<sub>25</sub> regions. As they used the same value in their analysis of M83 (Long et al. 2014, ApJS, 212, 21, the source catalog from which is available in the HEASARC database as the <a href="/W3Browse/chandra/m83cxo.html">M83CXO</a> table), the two catalogs are directly comparable. This table was created by the HEASARC in January 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/827/46">CDS Catalog J/ApJ/827/46</a> files table4.dat, table5.dat and table6.dat. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/m33deepxmm
- Title:
- M 33 Deep XMM-Newton Survey X-Ray Source Catalog
- Short Name:
- M33DEEPXMM
- Date:
- 25 Apr 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:
- 25 Apr 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 .
- ID:
- ivo://nasa.heasarc/m31phatcxo
- Title:
- M 31 Disk Chandra PHAT Survey: X-Ray Source Catalog
- Short Name:
- M31PHATCXO
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The X-ray source populations within galaxies are typically difficult to identify and classify with X-ray data alone. The authors break through this barrier by combining deep new Chandra ACIS-I observations with extensive Hubble Space Telescope (HST) imaging from the Panchromatic Hubble Andromeda Treasury (PHAT) of the M 31 disk. They detect 373 X-ray sources down to 0.35-8.0keV flux of 10<sup>-15</sup>erg/cm<sup>-2</sup>/s over 0.4deg<sup>2</sup>, 170 of which are reported for the first time. The authors identify optical counterpart candidates for 188 of the 373 sources, after using the HST data to correct the absolute astrometry of our Chandra imaging to 0.1". While 58 of these 188 are associated with point sources potentially in M 31, over half (107) of the counterpart candidates are extended background galaxies, 5 are star clusters, 12 are foreground stars, and 6 are supernova remnants. Sources with no clear counterpart candidate are most likely to be undetected background galaxies and low-mass X-ray binaries in M 31. The hardest sources in the 1-8keV band tend to be matched to background galaxies. The 58 point sources that are not consistent with foreground stars are bright enough that they could be high-mass stars in M 31; however, all but 8 have optical colors inconsistent with single stars, suggesting that many could be background galaxies or binary counterparts. For point-like counterparts, the authors examine the star formation history of the surrounding stellar populations to look for a young component that could be associated with a high-mass X-ray binary. The associated star formation histories for sources in the catalog are available in the linked table <a href="/W3Browse/chandra/m31phatsfh.html">M31PHATSFH</a>. In 2015 October, the authors observed the Panchromatic Hubble Andromeda Treasury (PHAT) footprint with Chandra with 7 pointings. The footprints are overlaid on a GALEX NUV image of M 31, along with the corresponding HST coverage, in Figure 1 of the reference paper. At each pointing they observed for about 50ks in VF mode (Chandra ObsID 17008 to 17014 spanning 2015 Oct 06 to 2015 Oct 26). This table was created by the HEASARC in April 2020 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/239/13">CDS Catalog J/ApJS/239/13</a> file table4.dat and table6.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/m16cxo
- Title:
- M 16 (Eagle Nebula) Chandra X-Ray Point Source Catalog
- Short Name:
- M16CXO
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Mechanisms regulating the origin of X-rays in young stellar objects and the correlation with their evolutionary stage are under debate. Studies of the X-ray properties in young clusters allow us to understand these mechanisms. One ideal target for this analysis is the Eagle Nebula (M 16), with its central cluster NGC 6611. At 1750 pc from the Sun, it harbors 93 OB stars, together with a population of low-mass stars from embedded protostars to disk-less Class III objects, with age <= 3 Myr. The authors study an archival 78 ks Chandra/ACIS-I observation of NGC 6611 and two new 80-ks observations of the outer region of M 16, one centered on the Column V and the other on a region of the molecular cloud with ongoing star formation. They detect 1755 point sources with 1183 candidate cluster members (219 disk-bearing and 964 disk-less), studying the global X-ray properties of M 16 and comparing them with those of the Orion Nebula Cluster. The authors also compare the level of X-ray emission of Class II and Class III stars and analyze the X-ray spectral properties of OB stars. Their study supports the lower level of X-ray activity for the disk-bearing stars with respect to the disk-less members. The X-ray luminosity function (XLF) of M 16 is similar to that of Orion, supporting the universality of the XLF in young clusters. Eighty-five percent of the O-type stars of NGC 6611 have been detected in X-rays. With only one possible exception, they show soft spectra with no hard components, indicating that mechanisms for the production of hard X-ray emission in O stars are not operating in NGC 6611. The determination of the absorption corrected X-ray luminosity (L<sub>X</sub>), as well as the plasma temperature (kT) and hydrogen column density (N<sub>H</sub>), requires the analysis of the X-ray spectra. The authors fit the observed spectra with thermal plasma (with both one and two temperatures) and power-law models. They use the APEC ionization-equilibrium thermal plasma code, assuming the sub-solar elemental abundances of Maggio et al. (2007, APJ, 660, 1462). The absorption was treated using the WABS model. The one-temperature (1T) thermal model was applied to all the sources with more than 25 counts, while the two-temperature (2T) thermal model was applied to each source with more than 80 counts. The power-law model has been applied to those sources with hard spectra for which the best-fit thermal model predicts a plasma temperature kT > 5 keV. When more than one model has been used for a given source, the authors chose the best model by the chi-squared probability and visual inspection of the spectrum. This table contains a description of the X-ray properties of 1754 sources (one less than stated in the abstract of the reference paper) derived from three Chandra/ACIS-I observations, together with a source classification based on the optical and infrared properties of each source. Data come from three ACIS-I observations (central or 'c', east or 'e', and north-east or 'ne') and many values are not averaged but presented for each observation as indicated by the parameter prefixes 'c_', 'e_', and 'ne_', respectively. Source detection has been performed with PWDetect, adopting a threshold corresponding to 10 spurious detections. The HEASARC eliminated the 3 parameters describing the plasma temperature of the second spectral component and its associated negative and positive errors for sources in the north-east observation, as these were blank for all entries in the original table as obtained from the CDS. This table was created by the HEASARC in March 2013 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/753/117">CDS Catalog J/ApJ/753/117</a> file xraycat.dat. Some of the values for the alt_name parameter in the HEASARC's implementation of this table were corrected in April 2018. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/refnebulae
- Title:
- Merged Catalog of Reflection Nebulae
- Short Name:
- REFNEBULAE
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Several catalogs of reflection nebulae have been merged to create a uniform catalog of 913 objects. It contains revised coordinates, cross-identifications of nebulae and stars, as well as identifications with IRAS point sources. The HEASARC has endeavored to render all identifications of the nebulae in the various catalogs according to the styles recommended by the Dictionary of Nomenclature of Celestial Objects. This table was created by the HEASARC in October 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/399/141">CDS Catalog J/A+A/399/141</a> file table1.dat. This is a service provided by NASA HEASARC .
507. Messier Nebulae
- ID:
- ivo://nasa.heasarc/messier
- Title:
- Messier Nebulae
- Short Name:
- Messier
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Messier Catalog of bright, extended objects was compiled by the comet-hunter Charles Messier in the 18th century. It comprised a list of 110 objects which are mostly brighter than 10th magnitude and have angular sizes from 1 to 100 arcminutes. M 102 is now generally considered to be spurious, and the object so named was actually M 101. Hence this electronic version of the Messier Catalog contains only 109 objects. The objects in the Messier Catalog are predominantly star clusters in our Milky Way galaxy, with 29 of them being globular clusters, 27 open clusters; the rest are spiral galaxies (27), elliptical galaxies (11), diffuse and planetary nebulae (10), and miscellaneous objects (5). All of the objects in the Messier Catalog are north of -35 degrees declination. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/m31stars
- Title:
- M 31 Field Brightest Stars Catalog
- Short Name:
- M31Stars
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Thie database table is a catalog of 11438 stars in the field of M31 and 8778 stars in 2 nearby "foreground" fields. It is based on a set of Tautenburg Schmidt plates in U, B, V, and R taken by van den Bergh. The range of visual magnitudes of stars is 11.5 < V < 20. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/m31clustrs
- Title:
- M 31 Globular Cluster Candidates Catalog
- Short Name:
- M31/GC
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table contains a list of 288 globular cluster candidates and 132 miscellaneous objects found in a 70 arcminute square field centered on the M 31 (Andromeda) Galaxy. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/msxpsc
- Title:
- Midcourse Space Experiment (MSX) Point Source Catalog, V2.3
- Short Name:
- MSX
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the main catalog from Version 2.3 of the Midcourse Space Experiment (MSX) Point Source Catalog (PSC), which supersedes the previous version (1.2) that was released in 1999, and contains 100,000 more sources than the latter. The MSX PSC main catalog used to create this Browse table contains all the sources found in the Galactic Plane survey, and the primary high-latitude regions (the IRAS gaps regions, and the Large Magellanic Cloud). Note that this HEASARC table does not contain the MSX PSC supplementary catalogs, viz. the singleton catalog, the low-reliability catalog, or the minicatalogs for 19 selected regions. The principal objective of the astronomy experiments onboard the MSX satellite was to complete the census of the mid-infrared (4.2-25 micron or um) sky: namely, the areas missed by the IRAS mission (about 4% of the sky was not surveyed by IRAS), and the Galactic Plane (where the sensitivity of IRAS was degraded by confusion noise in regions of high source densities or of structured extended emission). The photometry is based on co-added image plates, as opposed to single-scan data, which results in improved sensitivity and hence reliability in the fluxes. Comparison with Tycho-2 positions indicates that the astrometric accuracy of the new catalog is more than 1" better than that in Version 1.2. The infrared instrument on MSX was named SPIRIT III; it was a 35-cm clear aperture off-axis telescope with five line scanned infrared focal-plane arrays of 18.3 arcseconds square pixels, with a high sensitivity (0.1 Jy at 8.3 um). The filter characteristics of the 6 spectral bands B1, B2, A, C, D and E are summarized below, where all wavelengths are in micron (µm): <pre> Band Center FWHM Points ---------------------------- B1 4.29 um 4.22 - 4.36 um B2 4.35 4.24 - 4.45 A 8.28 6.8 - 10.8 C 12.13 11.1 - 13.2 D 14.65 13.5 - 15.9 E 21.34 18.2 - 25.1 </pre> The MSX catalog names of the sources have been defined according to International Astronomical Union (IAU) conventions with a unique identifier combined with the position of the source. In this case, the MSX PSC V2.3 sources are named using the convention MSX6C GLLL.llll+/-BB.bbbb, where MSX6C denotes that this is MSX data run using Version 6.0 of the CONVERT software, and GLLL.llll+/-BB.bbbb gives the Galactic coordinates of the source. This database table was first created by the HEASARC in November 2002 and then updated in April 2005, based on the 11-Dec-2003 version of the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/V/114">CDS Catalog V/114</a> (specifically, the files gb_gt6.dat, gp_m05m2.dat, gp_m2m6.dat, gp_p05p2.dat, gp_p2p6.dat, and gp_pm05.dat which comprise the main catalog). This is a service provided by NASA HEASARC .
