- ID:
- ivo://nasa.heasarc/xmmslewcln
- Title:
- XMM-Newton Slew Survey Clean Source Catalog, v2.0
- Short Name:
- XMMSlewClean
- Date:
- 01 Nov 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the 'clean' sample of sources from the second catalog of X-ray sources found in slew data taken by the European Space Agency's XMM-Newton Observatory, XMMSL2 or XMMSLEW, Version 2.0. It has been constructed by members of the XMM-Newton Science Operations Centre (SOC) and the European Photon Imaging Camera (EPIC) consortium on behalf of ESA. This release uses results of work which was carried out within the framework of the EXTraS project ("Exploring the X-ray variable and Transient Sky"), funded from the EU's Seventh Framework Programme under grant agreement no.607452. This is the first release of XMMSL2 which contains data taken between revolutions 314 and 2758. The previous catalog was called XMMSL1_Delta6 and contained slews up to revolution 2441. XMMSL2 has been generated from 2114 slews, executed between 2001-08-26 and 2014-12-31, revolutions 314 to 2758. Not all slews made in this period have been used; slews with particularly high background throughout the slew or which gave processing problems have been rejected. A full discussion of the differences between XMMSL2 and XMMSL1 is given in Section 12 of the XMMSL2 Users Guide at <a href="https://www.cosmos.esa.int/web/xmm-newton/xmmsl2-ug">https://www.cosmos.esa.int/web/xmm-newton/xmmsl2-ug</a>. This database table was first created by the HEASARC in August 2007 based on the FITS version of XMMSL1D1 (v1.1) of the XMM Slew Catalog. The current version was created in April 2017 based on the FITS version of XMMSL2 (v2.0) of the XMM Slew Catalog obtained from the following URLs: <a href="http://nxsa.esac.esa.int/catalogues/xmmsl2_clean.fits.gz">http://nxsa.esac.esa.int/catalogues/xmmsl2_clean.fits.gz</a> (the clean sample), and <a href="http://nxsa.esac.esa.int/catalogues/xmmsl2_total.fits.gz">http://nxsa.esac.esa.int/catalogues/xmmsl2_total.fits.gz</a> (the total sample). <p> The HEASARC has endeavored to retain the same parameter names as in the ESA version, but has changed some so as to conform to the standard HEASARC parameters naming conventions, e.g., all error parameter names which ended in "_err" in the ESA version end in "_error" in this HEASARC version. For other parameters which have had their names changed, their original ESA names are listed in square brackets in their descriptions below. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/xmmslewegs
- Title:
- XMM-Newton Slew Survey Extragalactic Sample
- Short Name:
- XMMSLEWEGS
- Date:
- 01 Nov 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The ongoing XMM-Newton Slew Survey (XSS) provides coverage of a significant fraction of the sky in a broad X-ray bandpass. Although shallow by contemporary standards, in the "classical" 2-10 keV band of X-ray astronomy the XSS provides significantly better sensitivity than any currently available all-sky survey. The authors investigate the source content of the XSS, focusing on detections in the hard 2-10 keV band down to a very low threshold (>= 4 counts net of background). At the faint end, the survey reaches a flux sensitivity of roughly 3 x 10<sup>-12</sup> erg/cm<sup>2</sup>/s (2-10 keV). The starting point was a sample of 487 sources detected in the XSS (up to and including release XMMSL1d2) at high galactic latitude in the hard band. Through cross-correlation with published source catalogs from surveys spanning the electromagnetic spectrum from radio through to gamma-rays, they find that 45% of the sources have likely identifications with normal/active galaxies. A further 18% are associated with other classes of X-ray object (nearby coronally active stars, accreting binaries, clusters of galaxies), leaving 37% of the XSS sources with no current identification. The authors go on to define an XSS extragalactic sample comprised of 219 galaxies and active galaxies selected in the XSS hard band. They investigate the properties of this extragalactic sample including its X-ray log N - log S distribution, and it is this sample that is contained in this table. The authors find that, in the low-count limit, the XSS is, as expected, strongly affected by Eddington bias. There is also a very strong bias in the XSS against the detection of extended sources, most notably clusters of galaxies. A significant fraction of the detections at and around the low-count limit may be spurious. Nevertheless, it is possible to use the XSS to extract a reasonably robust sample of extragalactic sources, excluding galaxy clusters. The differential log N - log S relation of these extragalactic sources matches very well to the HEAO-1 A2 all-sky survey measurements at bright fluxes and to the 2XMM source counts at the faint end. The substantial sky coverage afforded by the XSS makes this survey a valuable resource for studying X-ray bright source samples, including those selected specifically in the hard 2 - 10 keV band. This table was created by the HEASARC in December 2012, based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/548/A99">CDS Catalog J/A+A/548/A99</a> file tablea1.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/xmmslewful
- Title:
- XMM-Newton Slew Survey Full Source Catalog, v2.0
- Short Name:
- XMMSlewFull
- Date:
- 01 Nov 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the 'total' sample of sources from the second catalog of X-ray sources found in slew data taken by the European Space Agency's XMM-Newton Observatory, XMMSL2 or XMMSLEW, Version 2.0. It has been constructed by members of the XMM-Newton Science Operations Centre (SOC) and the European Photon Imaging Camera (EPIC) consortium on behalf of ESA. This release uses results of work which was carried out within the framework of the EXTraS project ("Exploring the X-ray variable and Transient Sky"), funded from the EU's Seventh Framework Programme under grant agreement no.607452. This is the first release of XMMSL2 which contains data taken between revolutions 314 and 2758. The previous catalog was called XMMSL1_Delta6 and contained slews up to revolution 2441. XMMSL2 has been generated from 2114 slews, executed between 2001-08-26 and 2014-12-31, revolutions 314 to 2758. Not all slews made in this period have been used; slews with particularly high background throughout the slew or which gave processing problems have been rejected. A full discussion of the differences between XMMSL2 and XMMSL1 is given in Section 12 of the XMMSL2 Users Guide at <a href="https://www.cosmos.esa.int/web/xmm-newton/xmmsl2-ug">https://www.cosmos.esa.int/web/xmm-newton/xmmsl2-ug</a>. This database table was first created by the HEASARC in August 2007 based on the FITS version of XMMSL1D1 (v1.1) of the XMM Slew Catalog. The current version was created in April 2017 based on the FITS version of XMMSL2 (v2.0) of the XMM Slew Catalog obtained from the following URLs: <a href="http://nxsa.esac.esa.int/catalogues/xmmsl2_clean.fits.gz">http://nxsa.esac.esa.int/catalogues/xmmsl2_clean.fits.gz</a> (the clean sample), and <a href="http://nxsa.esac.esa.int/catalogues/xmmsl2_total.fits.gz">http://nxsa.esac.esa.int/catalogues/xmmsl2_total.fits.gz</a> (the total sample). <p> The HEASARC has endeavored to retain the same parameter names as in the ESA version, but has changed some so as to conform to the standard HEASARC parameters naming conventions, e.g., all error parameter names which ended in "_err" in the ESA version end in "_error" in this HEASARC version. For other parameters which have had their names changed, their original ESA names are listed in square brackets in their descriptions below. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/xmmatlas
- Title:
- XMM-Newton Survey Catalog in the Herschel-ATLAS Field
- Short Name:
- XMMATLAS
- Date:
- 01 Nov 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Wide area X-ray and far-infrared surveys are a fundamental tool to investigate the link between AGN growth and star formation, especially in the low-redshift universe (z < 1). The Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) has covered 550 deg<sup>2</sup> in five far-infrared and sub-mm bands, 16 deg<sup>2</sup> of which have been presented in the Science Demonstration Phase (SDP) catalogue. The reference paper cited below introduces the XMM-Newton observations in the H-ATLAS SDP area, covering 7.1 deg<sup>2</sup> with flux limits of 2 x 10<sup>-15</sup>, 6 x 10<sup>-15</sup>, and 9 x 10<sup>-15</sup> erg/s/cm<sup>2</sup> in the 0.5-2, 0.5-8 and 2-8keV bands, respectively. The paper presents the source detection techniques and the "main" catalog, which includes 1700, 1582 and 814 sources detected by EMLDetect in the 0.5-8, 0.5-2 and 2-8keV bands, respectively; the number of unique sources is 1816. The authors extract spectra and derive fluxes from power-law fits for 398 sources with more than 40 counts in the 0.5-8 keV band. They compare the best-fit fluxes with those in the catalog, which were obtained assuming a common photon index Gamma of 1.7; the authors find no bulk difference between the fluxes, and a moderate dispersion s of 0.33 dex. Using wherever possible the fluxes from the spectral fits, the authors derive the 2-10 keV Log N-Log S distribution, which is consistent with a Euclidean distribution. Finally, they release the computer code for the tools which they developed for this project. Sources were detected with a two-stage process. With the first pass at low significance, the authors got a list of candidate detections; and on the second pass they raised the significance threshold and derived accurate source parameters. Between the two passes, and because the second pass needs an input catalog, they identified the sources detected in more than one band. In the first pass, the SAS wavelet detection program ewavelet was run separately on each of the 0.5-2, 2-8 and 0.5-8 keV images of the entire mosaic, with a significance threshold of 4 sigma and the default wavelet scales (minimum 2 pixels, maximum 8 pixels, with a pixel size of 4). All parameters in this catalog which were derived from ewavelet have been given a prefix of 'wav' in this HEASARC representation so as to distinguish them from the parameters derived using EMLDetect. In the second pass, the authors used the SAS EMLDetect program to validate the detections, refine the coordinates and obtain maximum-likelihood estimates of the source counts, count rates and fluxes. The EMLDetect minimum likelihood was set at L = 4.6, as in Ranalli et al. (2013, A&A, 555, A42), which corresponds to a false-detection probability of 1.01 x 10<sup>-2</sup>. Together with the 4-sigma threshold for ewavelet, for the final catalog this yields a joint significance between 4 sigma and 5 sigma, but which cannot be further constrained without simulations. This table contains the X-ray sources which were detected in the 7.1 deg<sup>2</sup> XMM-Newton observations of the H-ATLAS field. The 1816 sources which were detected by both programs were presented in the main table in the reference paper (and are included in this HEASARC table where they are indicated by a value of the source_sample parameter of 'main'), while the 234 sources which were only detected by ewavelet were presented in the supplementary table in the reference paper (and are included in this HEASARC table where they are indicated by a value of the source_sample parameter of 'supp'). The same parameters were present in both the main and supplementary tables in the reference paper, but those parameters which came from EMLDetect are empty for the sources in the supplementary table. The parameters obtained using ewavelet (those parameters with the 'wav' prefix in their names) containing the source properties (counts, count rates, fluxes, exposure times, background, wavelet detection scale and source extent), while reported in this table for all sources, are actually only interesting for supplementary sources, according to the authors. This table was created by the HEASARC in May 2015 based on the union of <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/577/A121">CDS Catalog J/A+A/577/A121</a> files main.dat (which contain 1816 sources detected by both detection algorithms) and suppl.dat (which contains 234 'supplementary' sources detected only by the wavelet detection algorithm ewavelet). It thus contains a total of 2050 sources. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/xmmsscgps
- Title:
- XMM-Newton Survey Science Center Survey of the Galactic Plane
- Short Name:
- XMMSSCGPS
- Date:
- 01 Nov 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Many different classes of X-ray sources contribute to the Galactic landscape at high energies. Although the nature of the most luminous X-ray emitters is now fairly well understood, the population of low-to-medium X-ray luminosity (L<sub>X</sub> = 10<sup>27</sup> - 10<sup>34</sup> erg/s) sources remains much less studied, our knowledge being mostly based on the observation of local members. The advent of wide-field and high-sensitivity X-ray telescopes such as XMM-Newton now offers the opportunity to observe this low-to-medium L<sub>X</sub> population at large distances. This study reports the results of a Galactic plane survey conducted by the XMM-Newton Survey Science Centre (SSC). Beyond its astrophysical goals, this survey aims at gathering a representative sample of identified X-ray sources at low latitude that can be used later on to statistically identify the rest of the serendipitous sources discovered in the Milky Way. The survey is based on 26 XMM-Newton observations, obtained at |b| < 20 degrees, distributed over a large range in Galactic longitudes and covering a summed area of 4 deg<sup>2</sup>. The flux limit of this survey is 2 x 10<sup>-15</sup> erg/cm<sup>2</sup>/s in the soft (0.5 - 2 keV) band and 1 x 10<sup>-14</sup> erg/cm<sup>2</sup>/s in the hard (2 - 1 2keV) band. A total of 1319 individual X-ray sources have been detected. Using optical follow-up observations supplemented by cross-correlation with a large range of multi-wavelength archival catalogs, the authors identify 316 X-ray sources. This constitutes the largest group of spectroscopically identified low-latitude X-ray sources at this flux level. The majority of the identified X-ray sources are active coronae with spectral types in the range A to M at maximum distances of ~1 kpc. The number of identified active stars increases towards late spectral types, reaching a maximum at K. Using infrared colors, the authors classify 18% of the stars as giants. The observed distributions of F<sub>X</sub>/F<sub>V</sub>, X-ray and infrared colors indicates that their sample is dominated by a young (100 Myr) to intermediate (600 Myr) age population with a small contribution of close main-sequence or evolved binaries. The authors find other interesting objects such as cataclysmic variables (d ~ 0.6 - 2 kpc), low-luminosity high-mass stars (likely belonging to the class of Gamma-Cas-like systems, d ~ 1.5 - 7 kpc), T Tauri and Herbig-Ae stars. A handful of extragalactic sources located in the highest Galactic latitude fields could be optically identified. For the 20 fields observed with the EPIC pn camera, the authors have constructed log N(>S) - log S curves in the soft and hard bands. In the soft band, the majority of the sources are positively identified with active coronae and the fraction of stars increases by about one order of magnitude from b = 60 degrees to b = 0 degrees at an X-ray flux of 2 x 10<sup>-14</sup> erg/cm<sup>2</sup>/s. The hard band is dominated by extragalactic sources, but there is a small contribution from a hard Galactic population formed by CVs, HMXB candidates or Gamma-Cas-like systems and by some active coronal stars that are also detected in the soft band. At b = 0 degrees, the surface density of hard sources brighter than 1 x 10<sup>-13</sup> erg/cm<sup>2</sup>/s steeply increases by one order of magnitude from l = 20 degrees to the Galactic center region (l = 0.9 degrees). This HEASARC table contains 739 X-ray sources detected in the 26 different fields observed in this study and listed in Tables 8 - 33, inclusive, of the reference paper. These 739 sources have the best XMM quality, i.e. the summary flag sum_flag which contains information about flags set automatically and manually for a given source is zero, meaning that there are no negative flags for the source detection, have either a 2MASS, USNO, GSC, or SDSS counterpart, whatever the probability of identification is, or have some information via SIMBAD or the authors own imaging or spectroscopic observations. For each X-ray source, its X-ray parameters are summarized, listing the pn count rates, and information on optical and infrared counterparts is provided. The properties of the 26 target fields are given in Table 1 of the reference paper, along with the breakdown of source classes in each field. This table was created by the HEASARC in May 2013 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/553/A12">CDS Catalog J/A+A/553/A12</a>, the 26 files table8.dat to table33.dat, inclusive. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/xwas
- Title:
- XMM-Newton Wide Angle Survey
- Short Name:
- XWAS
- Date:
- 01 Nov 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains results from the XMM-Newton Wide Angle Survey (XWAS), viz., a new catalog of almost a thousand X-ray sources that have been spectroscopically identified through optical observations. The sources lie in high-galactic latitude (|b| > 20 degrees) XMM-Newton fields mainly in the southern hemisphere. A sample of X-ray sources detected in 68 XMM-Newton pointed observations was selected for optical multi-fiber spectroscopy. Optical counterparts and corresponding photometry of the X-ray sources were obtained from the SuperCOSMOS Sky Survey. Candidates for spectroscopy were initially selected with magnitudes down to R ~ 21, with preference for X-ray sources having a flux F<sub>0.5-4.5keV</sub> >= 10<sup>-14</sup> erg/s/cm<sup>2</sup>. Optical spectroscopic observations were made using the Two Degree Field of the Anglo-Australian Telescope, and the resulting spectra were classified based on optical emission lines. The authors have identified through optical spectroscopy 940 X-ray sources over a solid angle Omega ~ 11.8 deg<sup>2</sup> of the sky. Source populations in their sample can be summarized as 65% broad-line active galactic nuclei (BLAGN), 16% narrow emission-line galaxies (NELGs), 6% absorption-line galaxies (ALGs) and 13% stars. An active nucleus is also likely to be present in the large majority of the X-ray sources spectroscopically classified as NELGs or ALGs. Optical images are available for all of the XWAS fields in the SuperCOSMOS Sky Survey (Hambly et al., 2001, MNRAS, 326, 1279). This table was created by the HEASARC in May 2017 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/557/A123">CDS Catalog J/A+A/557/A123</a> file xwas_cat.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/xmmxassist
- Title:
- XMM-Newton XAssist Source List
- Short Name:
- XMM/XAssist
- Date:
- 01 Nov 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table contains the latest XMM-Newton XAssist source list. XAssist is a NASA-funded project for the automation of X-ray astrophysics, with emphasis on galaxies. It is capable of data reprocessing, source detection, and preliminary spatial, temporal, and spectral analysis for all sources with sufficient counts. The bulk of the system is written in Python, which in turn drives underlying software to process the XMM-Newton data. Pipelines running on XMM-Newton observations of galaxies have generated the source list which comprises this HEASARC table. The pipeline also includes fields requested by users for various projects, most notably observations of a sample of quasars and several deep field observations have been processed. Note that the pipline processing is completely automated; therefore, users should visually inspect the results of any queries. This table was first created by the HEASARC in July 2005 based on the XMM source list available at the XAssist website. In December 2012, the HEASARC switched over to using the "pipeline5" XMM source list. It is updated on a weekly basis when and if the XAssist source list file at <a href="https://asd.gsfc.nasa.gov/xassist/pipeline5/xmm/master_srclist.csv">https://asd.gsfc.nasa.gov/xassist/pipeline5/xmm/master_srclist.csv</a> is updated. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/xmmssclwbs
- Title:
- XMM-Newton 2XMMi-DR3 Selected Source Classifications Catalog
- Short Name:
- XMMSSCLWBS
- Date:
- 01 Nov 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have carried out a classification of 4,330 X-ray sources in the 2XMMi-DR3 catalog. The sources were selected under the requirement of being a point source with multiple XMM-Newton observations and at least one detection with a signal-to-noise ratio larger than 20. For about one-third of the sources, the authors are able to obtain reliable source types from the literature. They mostly correspond to various types of stars (611), active galactic nuclei (AGNs, 753), and compact object systems (138) containing white dwarfs, neutron stars, and stellar-mass black holes. The authors find that about 99% of stars can be separated from other source types based on their low X-ray-to-IR flux ratios and frequent X-ray flares. AGNs have remarkably similar X-ray spectra, with the power-law photon index centered around 1.91 +/- 0.31, and their 0.2-4.5 keV flux long-term variation factors have a median of 1.48, with 98.5% being less than 10. In contrast, 70% of compact object systems can be very soft or hard, highly variable in X-rays, and/or have very large X-ray-to-IR flux ratios, separating them from AGNs. Using these results, the authors derive a source type classification scheme to classify the other sources and find 644 candidate stars, 1,376 candidate AGNs, and 202 candidate compact object systems, whose false identification probabilities are estimated to be about 1%, 3%, and 18%, respectively. There are still 320 sources associated with nearby galaxies and 151 in the Galactic plane, which the authors expect to be mostly compact object systems or background AGNs. There are also 100 candidate ultraluminous X-ray sources. They are found to be much less variable than other accreting compact objects. This table was created by the HEASARC in October 2012 based on an electronic version of Table 4 from the reference paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/xmmssclwbd
- Title:
- XMM-Newton 2XMMi-DR3 Selected Source Detections Catalog
- Short Name:
- XMMSSCLWBD
- Date:
- 01 Nov 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have carried out a classification of 4,330 X-ray sources in the 2XMMi-DR3 catalog. The sources were selected under the requirement of being a point source with multiple XMM-Newton observations and at least one detection with a signal-to-noise ratio larger than 20. For about one-third of the sources, the authors are able to obtain reliable source types from the literature. They mostly correspond to various types of stars (611), active galactic nuclei (AGNs, 753), and compact object systems (138) containing white dwarfs, neutron stars, and stellar-mass black holes. The authors find that about 99% of stars can be separated from other source types based on their low X-ray-to-IR flux ratios and frequent X-ray flares. AGNs have remarkably similar X-ray spectra, with the power-law photon index centered around 1.91 +/- 0.31, and their 0.2-4.5 keV flux long-term variation factors have a median of 1.48, with 98.5% being less than 10. In contrast, 70% of compact object systems can be very soft or hard, highly variable in X-rays, and/or have very large X-ray-to-IR flux ratios, separating them from AGNs. Using these results, the authors derive a source type classification scheme to classify the other sources and find 644 candidate stars, 1,376 candidate AGNs, and 202 candidate compact object systems, whose false identification probabilities are estimated to be about 1%, 3%, and 18%, respectively. There are still 320 sources associated with nearby galaxies and 151 in the Galactic plane, which the authors expect to be mostly compact object systems or background AGNs. There are also 100 candidate ultraluminous X-ray sources. They are found to be much less variable than other accreting compact objects. This table contains the list of 19,637 detections of the 4,330 unique X-ray sources which comprise the authors' sample. The list of 4,330 unique X-ray sources and their classifications is also available as the HEASARC XMMSSCLWBS table. This table was created by the HEASARC in October 2012 based on an electronic version of Table 3 from the reference paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/hcgxrbs
- Title:
- X-Ray Observations of Compact Group Galaxies
- Short Name:
- HCGXRBS
- Date:
- 01 Nov 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog presents the study of a sample of 15 compact groups (CGs) observed with Chandra/ACIS, Swift/UVOT and Spitzer/IRAC-MIPS for which archival data exist, allowing the authors to obtain SFRs, stellar masses, sSFRs and X-ray fluxes and luminosities for individual, off-nuclear point sources, which they summed to obtain total X-ray luminosities originating in off-nuclear point sources in a galaxy. Details on the Swift and Spitzer observations and data for systems in this sample can be found in Tzanavaris et al. (2010ApJ...716..556T) and Lenkic et al. (2016MNRAS.459.2948L). For Chandra/ACIS observations, see Tzanavaris et al. (2014ApJS..212....9T) and Desjardins et al. (2013ApJ...763..121D; 2014ApJ...790..132D). The authors obtained total galaxy X-ray luminosities, L<sub>X</sub>, originating from individually detected point sources in a sample of 47 galaxies in 15 compact groups of galaxies (CGs). For the great majority of the galaxies, they found that the detected point sources most likely are local to their associated galaxy, and are thus extragalactic X-ray binaries (XRBs) or nuclear active galactic nuclei (AGNs). For spiral and irregular galaxies, they found that, after accounting for AGNs and nuclear sources, most CG galaxies are either within the +/- 1 sigma scatter of the Mineo et al. L<sub>X</sub>-star formation rate (SFR) correlation or have higher L<sub>X</sub> than predicted by this correlation for their SFR. These "excesses" may be due to low metallicities and high interaction levels. For elliptical and S0 galaxies, after accounting for AGNs and nuclear sources, most CG galaxies were found to be consistent with the Boroson et al. L<sub>X</sub>-stellar mass correlation for low-mass XRBs, with larger scatter, likely due to residual effects such as AGN activity or hot gas. Assuming non-nuclear sources are low- or high-mass XRBs, the authors used appropriate XRB luminosity functions to estimate the probability that stochastic effects can lead to such extreme L<sub>X</sub> values. They found that, although stochastic effects do not in general appear to be important, for some galaxies there is a significant probability that high L<sub>X</sub> values can be observed due to strong XRB variability. This table was created by the HEASARC in May 2019 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/817/95">CDS Catalog J/ApJ/817/95</a> file table3.dat This is a service provided by NASA HEASARC .
