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Description
The XMMSSC table contains the Fourth XMM-Newton Serendipitous Source Catalog, Fourteenth Data Release, or 4XMM-DR14. 4XMM-DR14 is the fourth-generation catalog of serendipitous X-ray sources from the European Space Agency's (ESA) XMM-Newton observatory, and has been created by the XMM-Newton Survey Science Centre (SSC) on behalf of ESA. It is an incremental version of the the 4XMM catalog and contains 621 more observations and 51,884 more detections than the preceding 4XMM-DR13 catalog, which was made public in July 2023. In addition, the team provides spectra and lightcurves for more than 18,775 more detections than in 4XMM-DR13. The catalog contains source detections drawn from a total of 13,864 XMM-Newton EPIC observations made between 2000 February 1 and 2023 December 31; all datasets included were publicly available by 2023 December 31 but not all public observations are included in this catalog. For net exposure time >= 1ksec, the net area of the catalog fields taking account of the substantial overlaps between observations is ~1,383 deg<sup>2</sup>. 4XMM-DR13 contains 1,035,832 X-ray detections above the processing likelihood threshold of 6. These X-ray detections relate to 692,109 unique X-ray sources. A significant fraction of sources (135,324, 20%) have more than one detection in the catalog (up to 90 repeat observations in the most extreme case). The catalog distinguishes between extended emission and point-like detections. Parameters of detections of extended sources are only reliable up to the maximum extent measure of 80 arcseconds. There are 96,553 detections of extended emission, of which 22,147 are 'clean' (in the sense that they were not flagged). Due to intrinsic features of the instrumentation as well as some shortcomings of the source detection process, some detections are considered to be spurious or their parameters are considered to be unreliable. It is recommended to use a detection flag and an observation flag as filters to obtain what can be considered a 'clean' sample. There are 897,091 out of 1,035,832 detections that are considered to be clean (i.e., summary flag < 3). For 372,313 detections, EPIC time series and 372,603 detections, EPIC spectra were automatically extracted during processing, and a chi<sup>2</sup>-variability test was applied to the time series. 8,380 detections in the catalog are considered variable, within the timespan of the specific observation, at a probability of 10<sup>-5</sup> or less based on the null-hypothesis that the source is constant. Of these, 6,307 have a summary flag <3. The median flux (in the total photon-energy band 0.2 - 12 keV) of the catalog detections is ~ 2.2 x 10<sup>-14</sup> erg/cm<sup>2</sup>/s; in the soft energy band (0.2 - 2 keV) the median flux is ~ 5.2 x 10<sup>-15</sup>, and in the hard band (2 - 12 keV) it is ~1.2 x 10<sup>-14</sup>. About 23% have fluxes below 1 x 10<sup>-14</sup> erg/cm<sup>2</sup>/s. The flux values from the three EPIC cameras are, overall, in agreement to ~10% for most energy bands. The median positional accuracy of the catalog point source detections is generally < 1.57 arcseconds (with a standard deviation of 1.43 arcseconds). With 4XMM-DR14, the team also released 4XMM-DR14s, available from HEASARC as <a href="/W3Browse/xmm-newton/xmmstack.html">XMMSTACK</a>, a new version of the stacked catalog built from 10,336 4XMM-DR14 overlapping observations. 4XMM-DR14s contains 1,751 stacks (or groups). Most of the stacks are composed of 2 observations and the largest has 372. The catalog contains 427,524 sources, of which 329,972 have several contributing observations. Stacking observations allows yet fainter sources to be detected in sky regions observed more than once, increasing the number of detections and uncovering long-term variability on repeatedly observed objects. 4XMM-DR14s reaches a depth of ~2.5 x 10<sup>-15</sup> and ~6.8 x 10<sup>-15</sup> erg/cm<sup>2</sup>/s in the soft (0.2-2keV) and hard (2-12 keV) X-ray band, respectively. The energy bands used in the 4XMM-DR14 processing were the same as for the 3XMM catalog. The following are the basic energy bands: <pre> 1 = 0.2 - 0.5 keV 2 = 0.5 - 1.0 keV 3 = 1.0 - 2.0 keV 4 = 2.0 - 4.5 keV 5 = 4.5 - 12.0 keV </pre> while these are the broad energy bands: <pre> 6 = 0.2 - 2.0 keV soft band, no images made 7 = 2.0 - 12.0 keV hard band, no images made 8 = 0.2 - 12.0 keV total band 9 = 0.5 - 4.5 keV XID band </pre> This database table was last updated by the HEASARC in July 2024. It contains the 4XMM-DR14 catalog, released by ESA on 2024-07-09 and obtained from the XMM-Newton Survey Science Center Consortium (<a href="http://xmmssc.irap.omp.eu/Catalogue/4XMM-DR14/4XMM_DR14.html">http://xmmssc.irap.omp.eu/Catalogue/4XMM-DR14/4XMM_DR14.html</a>). It is also available as a gzipped FITS file at <a href="https://heasarc.gsfc.nasa.gov/FTP/xmm/data/catalogues/4XMM_DR13cat_v1.0.fits.gz">https://heasarc.gsfc.nasa.gov/FTP/xmm/data/catalogues/4XMM_DR13cat_v1.0.fits.gz</a>. <p> The previous versions of the Serendipitous Source Catalog, 3XMM-DR5, 3XMM-DR6, 3XMM-DR7, 3XMM-DR8, 4XMM-DR9, 4XMM-DR10, 4XMM-DR11, 4XMM-DR12, and 4XMM-DR13 are also available in the same directory for comparison purposes as the files 3XMM_DR5cat_v1.0.fits.gz, 3XMM_DR6cat_v1.0.fits.gz, 3XMM_DR7cat_v1.0.fits.gz, 3XMM_DR8_cat_v1.0.fits.gz, 4XMM_DR9_cat_v1.0.fits.gz, 4XMM_DR10cat_v1.0.fits.gz, 4XMM_DR11cat_v1.0.fits.gz, and 4XMM_DR12cat_v1.0.fits.gz, 4XMM_DR13cat_v1.0.fits.gz, respectively. This is a service provided by NASA HEASARC .
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