- ID:
- ivo://nasa.heasarc/sacshpscat
- Title:
- SwiftAGN&ClusterSurvey(SACS)Hard-Band(2-10keV)PointSourceCatalog
- Short Name:
- SACSHPSCAT
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Swift Active galactic nucleus (AGN) and Cluster Survey (SACS) uses 125 deg<sup>2</sup> of Swift X-ray Telescope (XRT) serendipitous fields with variable depths surrounding gamma-ray bursts to provide a medium depth (4 x 10<sup>-15</sup> erg cm<sup>-2</sup> s<sup>-1</sup>) and medium area survey filling the gap between deep, narrow Chandra/XMM-Newton surveys and wide, shallow ROSAT surveys. In the reference paper, a catalog of 22,563 point sources and 442 extended sources, and the number counts of the AGN and galaxy cluster populations are presented. SACS provides excellent constraints on the AGN number counts at the bright end with negligible uncertainties due to cosmic variance, and these constraints are consistent with previous measurements. The authors use Wide-field Infrared Survey Explorer (WISE) mid-infrared(MIR) colors to classify the sources. For AGNs, they can roughly separate the point sources into MIR-red and MIR-blue AGNs, finding roughly equal numbers of each type in the soft X-ray band (0.5-2.0 keV), but fewer MIR-blue sources in the hard X-ray band (2-8 keV). The cluster number counts, with 5% uncertainties from cosmic variance, are also consistent with previous surveys but span a much larger continuous flux range. Deep optical or IR followup observations of this cluster sample will significantly increase the number of higher redshift (z > 0.5) X-ray-selected clusters. This HEASARC table contains the list of 10,060 Swift XRT point sources which were detected in the hard X-ray band image (2-10 keV) using wavdetect with a false positive threshold of 10<sup>-6</sup> (contained in Table 3 of the reference paper). The authors consider these sources to be AGN candidates. This table was created by the HEASARC in June 2015 based on an electronic version of Table 3 of the reference paper, the list of Swift XRT point sources detected in the hard X-ray (2-10 keV) band, which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/sacssescat
- Title:
- SwiftAGN&ClusterSurvey(SACS)Soft-Band(0.5-2keV)ExtendedSourceCatalog
- Short Name:
- SACSSESCAT
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Swift Active galactic nucleus (AGN) and Cluster Survey (SACS) uses 125 deg<sup>2</sup> of Swift X-ray Telescope (XRT) serendipitous fields with variable depths surrounding gamma-ray bursts to provide a medium depth (4 x 10<sup>-15</sup> erg cm<sup>-2</sup> s<sup>-1</sup>) and medium area survey filling the gap between deep, narrow Chandra/XMM-Newton surveys and wide, shallow ROSAT surveys. In the reference paper, a catalog of 22,563 point sources and 442 extended sources, and the number counts of the AGN and galaxy cluster populations are presented. SACS provides excellent constraints on the AGN number counts at the bright end with negligible uncertainties due to cosmic variance, and these constraints are consistent with previous measurements. The authors use Wide-field Infrared Survey Explorer (WISE) mid-infrared(MIR) colors to classify the sources. For AGNs, they can roughly separate the point sources into MIR-red and MIR-blue AGNs, finding roughly equal numbers of each type in the soft X-ray band (0.5-2.0 keV), but fewer MIR-blue sources in the hard X-ray band (2-8 keV). The cluster number counts, with 5% uncertainties from cosmic variance, are also consistent with previous surveys but span a much larger continuous flux range. Deep optical or IR followup observations of this cluster sample will significantly increase the number of higher redshift (z > 0.5) X-ray-selected clusters. This HEASARC table contains the list of 442 Swift XRT extended sources which were detected in the soft X-ray band image (0.5-2 keV) and contained in Table 4 of the reference paper. The authors defined the extended source catalog as those sources with S/N >= 4 and a minimum net photon count of 20 that are more than 3 sigma from the mean size of point sources for both their off-axis angle and S/N. The authors consider these extended sources to be candidate clusters of galaxies. This table was created by the HEASARC in July 2015 based on an electronic version of Table 4 of the reference paper, the list of Swift XRT extended sources detected in the soft X-ray (0.5-2 keV) band, which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/sacsspscat
- Title:
- SwiftAGN&ClusterSurvey(SACS)Soft-Band(0.5-2keV)PointSourceCatalog
- Short Name:
- SACSSPSCAT
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Swift Active galactic nucleus (AGN) and Cluster Survey (SACS) uses 125 deg<sup>2</sup> of Swift X-ray Telescope (XRT) serendipitous fields with variable depths surrounding gamma-ray bursts to provide a medium depth (4 x 10<sup>-15</sup> erg cm<sup>-2</sup> s<sup>-1</sup>) and medium area survey filling the gap between deep, narrow Chandra/XMM-Newton surveys and wide, shallow ROSAT surveys. In the reference paper, a catalog of 22,563 point sources and 442 extended sources, and the number counts of the AGN and galaxy cluster populations are presented. SACS provides excellent constraints on the AGN number counts at the bright end with negligible uncertainties due to cosmic variance, and these constraints are consistent with previous measurements. The authors use Wide-field Infrared Survey Explorer (WISE) mid-infrared(MIR) colors to classify the sources. For AGNs, they can roughly separate the point sources into MIR-red and MIR-blue AGNs, finding roughly equal numbers of each type in the soft X-ray band (0.5-2.0 keV), but fewer MIR-blue sources in the hard X-ray band (2-8 keV). The cluster number counts, with 5% uncertainties from cosmic variance, are also consistent with previous surveys but span a much larger continuous flux range. Deep optical or IR followup observations of this cluster sample will significantly increase the number of higher redshift (z > 0.5) X-ray-selected clusters. This HEASARC table contains the list of 17,748 Swift XRT point sources which were detected in the soft X-ray band image (0.5-2.0 keV) using wavdetect with a false positive threshold of 10<sup>-6</sup> (contained in Table 2 of the reference paper). The authors consider these sources to be AGN candidates. This table was created by the HEASARC in June 2015 based on an electronic version of Table 2 of the reference paper, the list of Swift XRT point sources detected in the soft X-ray (0.5-2 keV) band, which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/sacstpscat
- Title:
- SwiftAGN&ClusterSurvey(SACS)Total-Band(0.2-10keV)PointSourceCatalog
- Short Name:
- SACSTPSCAT
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Swift Active galactic nucleus (AGN) and Cluster Survey (SACS) uses 125 deg<sup>2</sup> of Swift X-Ray Telescope (XRT) serendipitous fields with variable depths surrounding gamma-ray bursts to provide a medium depth (4 x 10<sup>-15</sup> erg cm<sup>-2</sup> s<sup>-1</sup>) and medium area survey filling the gap between deep, narrow Chandra/XMM-Newton surveys and wide, shallow ROSAT surveys. In the reference paper, a catalog of 22,563 point sources and 442 extended sources, and the number counts of the AGN and galaxy cluster populations are presented. SACS provides excellent constraints on the AGN number counts at the bright end with negligible uncertainties due to cosmic variance, and these constraints are consistent with previous measurements. The authors use Wide-field Infrared Survey Explorer (WISE) mid-infrared(MIR) colors to classify the sources. For AGNs, they can roughly separate the point sources into MIR-red and MIR-blue AGNs, finding roughly equal numbers of each type in the soft X-ray band (0.5-2.0 keV), but fewer MIR-blue sources in the hard X-ray band (2-8 keV). The cluster number counts, with 5% uncertainties from cosmic variance, are also consistent with previous surveys but span a much larger continuous flux range. Deep optical or IR followup observations of this cluster sample will significantly increase the number of higher redshift (z > 0.5) X-ray-selected clusters. This HEASARC table contains the list of 22,563 Swift XRT point sources which were detected in the total X-ray band image (0.2-10 keV) using wavdetect with a false positive threshold of 10<sup>-6</sup> (contained in Table 1 of the reference paper). The authors consider these sources to be AGN candidates. This table was created by the HEASARC in June 2015 based on an electronic version of Table 1 of the reference paper, the list of Swift XRT point sources detected in the total X-ray (0.2-10 keV) band, which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/swbat105m
- Title:
- Swift-BAT 105-Month All-Sky Hard X-Ray Survey
- Short Name:
- SWBAT105M
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The catalog includes hard X-ray sources detected in the first 105-months of observations with the Burst Alert Telescope (BAT) coded-mask imager on board the Swift observatory. The 105-month Swift-BAT survey is a uniform hard X-ray all-sky survey with a sensitivity of 8.40x10<sup>-12</sup>erg/s/cm<sup>2</sup> over 90% of the sky and 7.24x10<sup>-12</sup>erg/s/cm<sup>2</sup> over 50% of the sky in the 14-195 keV band. The Swift-BAT 105-month catalog provides 1632 (422 new detections) hard X-ray sources in the 14-195 keV band above the 4.8 sigma significance level. Adding to the previously known hard X-ray sources, 34% (144/422) of the new detections are identified as Seyfert active galactic nuclei (AGNs) in nearby galaxies (z<0.2). The majority of the remaining identified sources are X-ray binaries (7%, 31) and blazars/BL Lac objects (10%, 43). As part of this new edition of the Swift-BAT catalog, the authors release eight-channel spectra and monthly sampled light curves for each object in the online journal and at the <a href="https://swift.gsfc.nasa.gov/results/bs105mon/">Swift-BAT 105-month website</a>. The data reduction, analysis, and catalog generation of the Swift-BAT 105-month survey (between 2004 December and 2013 August) are conducted following the same procedures as in the Swift-BAT 70-month survey (Baumgartner+ 2013, J/ApJS/207/19). The catalog includes 1632 hard X-ray sources detected across the entire sky. Of these 1632 sources, 422 are new detections with respect to the 70-month catalog, and 320 are reported as hard X-ray sources for the first time. The Swift-BAT 105-month survey catalog contains 947 non-beamed AGNs detected in the hard X-ray band. The authors inspected soft X-ray images provided by Swift-XRT (3-10keV), Chandra (2-10keV), ASCA (2-10keV), and XMM-Newton (4-10keV) for the newly detected sources when available using 15 arcmin of matching radius. See section 2.1 of the paper for further explanations. This table was created by the HEASARC in March 2020 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/235/4">CDS Catalog J/ApJS/235/4</a> file table3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/sixsrvycat
- Title:
- Swift-INTEGRAL X-Ray (SIX) Survey Catalog
- Short Name:
- SIXSRVYCAT
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The supermassive black holes at the center of active galactic nuclei (AGNs) are surrounded by obscuring matter that can block nuclear radiation. Depending on the amount of blocked radiation, the flux from the AGN can be too faint to be detected by currently operating hard X-ray (above 15 keV) missions. At these energies, only ~1% of the intensity of the cosmic X-ray background (CXB) can be resolved into point-like sources that are AGNs. In this work, the authors address the question of undetected sources contributing to the CXB with a very sensitive and new hard X-ray survey: the Swift-INTEGRAL X-ray (SIX) survey, which is obtained with the new approach of combining the Swift/BAT and INTEGRAL/IBIS X-ray observations. The authors merge the observations of both missions, which enhances the exposure time and reduces systematic uncertainties. As a result, they obtain a new survey over a wide sky area of 6200 deg<sup>2</sup> covering the region of the North Ecliptic Pole (NEP) and extending to the contiguous Coma region that is more sensitive than the surveys of Swift/BAT or INTEGRAL/IBIS alone. Their sample comprises 113 sources having S/N ratios of above 4.8 sigma: 86 AGNs (Seyfert-like and blazars), 5 galaxies, 2 clusters of galaxies, 3 Galactic sources, 3 previously detected unidentified X-ray sources, and 14 unidentified sources. The scientific outcome from the study of the sample has been properly addressed to study the evolution of AGNs at a redshift below 0.4. The authors do not find any evolution using the 1/V<sub>max</sub> method. Their sample of faint sources is a suitable target for the new generation of hard X-ray telescopes with focusing techniques. This table was created by the HEASARC in August 2012 based on an electronic version of Table 2 from the reference paper which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/swiftft
- Title:
- Swift Serendipitous Survey in Deep XRT GRB Fields (SwiftFT)
- Short Name:
- SWIFTFT
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the SwiftFT catalog of point sources detected by the X-ray Telescope (XRT) on board the Swift satellite in observations centered on gamma-ray bursts (GRBs) during the first four years of operation (Jan 2005 - Dec 2008). Swift is a NASA mission with international participation dedicated to the gamma-ray burst study. It carries three instruments. The BAT is the large field of view instrument and operates in the 10-300 keV energy band; and two narrow field instruments, XRT and UVOT, that operate in the X-ray and UV/optical regime, respectively. The catalog was derived including pointing positions of the 374 fields centered on the GRBs covering a total area of ~32.55 square degrees. Since GRBs are distributed randomly in the sky, the survey covers totally unrelated parts of the sky, and is highly uniform courtesy of the XRT's stable point spread function and small vignetting correction factors. The observations for a particular field were merged together and the source search analysis was restricted to a circular area of 10 arcmin radius centered in the median of the individual observation aim points. The total exposure considering all the fields is of 36.8 Ms, with ~32% of the fields having more than 100 ks exposure time, and ~28% with exposure time in the range 50-100 ks. The catalog was generated by running the detection algorithm in the XIMAGE package version 4.4.1 that locates the point sources using a sliding-cell method. The average background intensity is estimated in several small square boxes uniformly located within the image. The position and intensity of each detected source are calculated in a box whose size maximizes the signal-to-noise ratio. The detect algorithm was run separately in the following three energy bands: 0.3-3 (Soft), 2-10 (Hard), and 0.3-10 (Full) keV. For each detections the three count rates in the soft, hard, and full bands are all corrected for dead times and vignetting using exposure maps and for the PSF. Hardness ratios are calculated using the three energy band and defined as HR = (c<sub>H</sub> - c<sub>S</sub>)/(c<sub>H</sub> + c<sub>S</sub>) where c<sub>S</sub> and c<sub>H</sub> are the count rates in the S(oft) and H(ard) bands, respectively. The catalog was cleaned of spurious and extended sources by visual inspection of all the observations. Count rates in the three bands were converted into flux in the 0.5-10, 0.5-2, and 2-10 keV energy bands, respectively. The flux was estimated using a power law spectrum with photon spectral index of 1.8 and a Galactic N<sub>H</sub> of 3.3 x 10<sup>20</sup> cm<sup>-2</sup>. Each row in the catalog is a unique source. The detections from the soft, hard, and full bands were merged into a single catalog using a matching radius of 6 arcsec and retaining detection with a significance level of being spurious <= 2 x 10<sup>-5</sup> in at least one band. There are 9387 total entries in the catalog. The SWIFTFT acronym honors both the Swift satellite and the memory of Francesca Tamburelli who made numerous crucial contributions to the development of the Swift-XRT data reduction software. This database table was created by the HEASARC in November 2021 based on the electronic version available from the ASI Data Center <a href="https://www.asdc.asi.it/xrtgrbdeep_cat/">https://www.asdc.asi.it/xrtgrbdeep_cat/</a> and published in the Astronomy and Astrophysics Journal. This catalog is also available as the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/528/A122">CDS catalog J/A+A/528/A122</a>. The HEASARC added the source_number parameter, a counter to numerically identify each source in the catalog, as well as Galactic coordinates and changed the source name from SWIFTFTJHHMMSS.s+DDMM.m to SWIFTFT JHHMMSS.s+DDMM.m, adding a space between the catalog prefix and the formatted J2000 coordinates. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/swuvotssc
- Title:
- Swift/UVOT Serendipitous Source Catalog, v1.1
- Short Name:
- SWUVOTSSC
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The first version of the Swift UVOT Serendipitous Source Catalog (UVOTSSC) provides positions and magnitudes, as well as errors and upper limits of confirmed sources, for observations taken from the start of operations in 2005 until October 1st of 2010. The first version of the UVOTSSC has been produced by processing the image data obtained from the Swift Ultraviolet and Optical Telescope (UVOT). The data processing was performed at the Mullard Space Science Laboratory (MSSL, University College London, U.K.) using Swift FTOOLS from NASA's High Energy Astrophysics Software package (HEASoft-6.11), with some customizing of the UVOT packages in order to get more complete source detection and to properly apply quality flags to those sources that were detected within the UVOT image artifacts. The total number of observations with 17'x17' images used for version 1 of the catalog is 23,059, giving 6,200,016 sources in total, of which 2,027,265 have multiple entries in the source table because they have been detected in more than one observation. Some sources were only observed in one filter. The total number of entries in the source table is 13,860,568. The S/N ratio for all sources exceeds 5 in at least one UVOT filter, the rest of the filters having a S/N greater than 3. U, B, V, UVW2, UVM2 and UVW1 refer to the filter bandpasses defined in the UVOT Filterwheel section of the MSSL documentation at <a href="http://www.mssl.ucl.ac.uk/www_astro/uvot/uvot_instrument/filterwheel/filterwheel.html">http://www.mssl.ucl.ac.uk/www_astro/uvot/uvot_instrument/filterwheel/filterwheel.html</a>. The initially released version of the catalog (2015) was done with the source identifier "SWIFTUVOT" for each source, and was made available in that form. The decision was subsequently made to rename the catalog sources by including the catalog version number. In addition, in a few instances multiple source IDs shared the same name (IAUNAME). They will be distinguished by having a letter a,b,c,.. appended to their name. Sources brighter than 0.96 counts per frame have not been included because their coincidence loss is too large to correct for. This HEASARC table contains version 1.1 of the Swift UVOT source table and contains 13,860,568 entries for the individual detections of 6,200,016 sources. The HEASARC has changed the names of many of the parameters from those given in the original table. In such cases, we have listed the original names in parentheses at the end of the parameter descriptions given below. There is a second related table which gives a summary of the observations from which the UVOTSSC sources listed in this table have been detected and measured, which is available at the HEASARC as the SWUVOTSSOB table. This table was created by the HEASARC in May 2017 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/II/339">CDS Catalog II/339</a> file uvotssc1.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/swxrt1fgl
- Title:
- Swift XRT Counterparts to Unidentified 1FGL Sources
- Short Name:
- SWXRT1FGL
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have analyzed all the archival X-ray data of 134 unidentified (unID) gamma-ray sources listed in the first Fermi/LAT (1FGL) catalog and subsequently followed up by the Swift/XRT. They constructed the spectral energy distributions (SEDs) from radio to gamma-rays for each X-ray source detected, and tried to pick up unique objects that display anomalous spectral signatures. In these analyses, they target all the 1FGL unID sources, using updated data from the second Fermi/LAT (2FGL) catalog on the Large Area Telescope (LAT) position and spectra. In the reference paper, the authors discuss the X-ray identification results and the SEDs of all 134 sources observed with the Swift/XRT. The selection criteria for the Fermi sources were as follows: (1) categorized as unID sources in the 1FGL catalog, (2) localized at high Galactic latitude |b| > 10 degrees, (3) observational data were made public by October 2011, and (4) the positional center of the Swift FoV is within 12 arcminutes of the 1FGL sources. Among 630 unID sources listed in the 1FGL catalog, this selection yielded 134 sources which were analyzed in this study. This table contains the list of the positions and 0.3-10 keV count rates of 267 Swift XRT sources which were detected with a signal-to-noise ratio (SNR) of 3 or more within the Swift/XRT field of views (FoV) of 112 of the 134 1FGL unID gamma-ray sources, with 22 of the 1FGL sources having no detected Swift XRT sources in their FoVs. The Swift XRT images of all 134 unID gamma-ray sources, the positions of the significant XRT sources, and the 95% 1FGL and 2FGL error ellipses are shown in Figure 11 of the reference paper. This table was created by the HEASARC in September 2014 based on an electronic version of Table 4 from the reference paper which was obtained from the ApJS website. Some of the values for the 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/swift2sxps
- Title:
- Swift-XRT Point Source Catalog (2SXPS)
- Short Name:
- SWIFT2SXPS
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the second Swift X-ray Point Source (2SXPS) catalog of detections by the Swift X-ray Telescope (XRT) used in Photon Counting (PC) mode in the 0.3-10 keV energy range. Swift is a NASA mission with international participation dedicated to the gamma-ray burst study. It carries three instruments. The BAT is the large field-of-view instrument and operates in the 10-300 keV energy band; and two narrow field instruments, XRT and UVOT, that operate in the X-ray and UV/optical regime, respectively. The overall 2SXPS catalog characteristics are as follows: <pre> Data included 2005 Jan 01 - 2018 August 01 Sky coverage 3,790 square degrees Typical Sensitivity (0.3-10 keV) 2x10<sup>-13</sup> erg cm<sup>-2</sup> s<sup>-1</sup> (observations) 4x10<sup>-14</sup> erg cm<sup>-2</sup> s<sup>-1</sup> (stacked images) Typical position error 5.6" (90% confidence radius, including systematics) Detections 1,091,058 Unique sources 206,335 Variable sources 82,324 Uncatalogued sources 78,100 False positive rate Flag=Good 0.3% Flag=Good/Reasonable 1% Flag=Good/Reasonable/Poor <10% </pre> This catalog enhances the 1SXPS catalogue (Evans, P. A., et al. 2014, ApJS, 210, 8) in different ways. The 2SXPS catalog uses an improved Point Spread Function (PSF) and pile-up models, a better source detection pipeline that includes a technique to model the effects of stray light, and tests to automatically avoid diffuse emission and ~six years more data. The results are that the 2SXPS catalog contains 50% more temporal coverage than 1SXPS, a sky coverage of 3790 square deg almost double compare to the 1SXPS (1905 square Degree) and ~30% more sources compared to the 1SXPS. The Swift XRT observations were filtered to remove times when: a) data were contaminated by scattered light from the daylight side of the Earth; b) the on-board astrometry derived from the images obtained by the Swift UV/Optical telescope was unreliable; and c) observations with less than 100s of PC mode. The 127519 observations included in the catalog provide a total usable exposure is 266.5 Ms. A Swift observation is a collection of snapshots and the source detection algorithm was run on individual observation as well as on stacked images. The latter were generated on a grid of 2,300x2,300 pixels (~ 90'x90') to ensure that every overlap between observations is in at least one stacked image. A total of 14628 stacked images were generated. Each record corresponds to a unique source which characteristics are described with 230 parameters. The catalog reports for each source rates in four energy band (0.3-10.keV, 0.3-1. keV, 1-2 keV and 3-10 keV), background rates, variability for each energy band, two hardness ratio, peak rate and several spectral parameters. The hardness ratios are defined as follows: <pre> HR1 = (M-S)/(M+S) where M and S are the medium (1-2 keV) and soft (0.3-1 keV) band count rates HR2 = (H-M)/(H+M) where H and M are the hard (2-10 keV) and medium (1-2 keV) band count rates </pre> and they are calculated using all observations. The peak rate is determined using three different timescale: the count rate considering all the observations (see parameters rates in this database), the count rate in each observation (not reported in this database) and the count rate in each snapshot (not reported in this database). The peak rate is the rate +/- error from the timescale which has the highest 1-sigma lower-limit on the count rate. Spectral parameters and source flux are estimated using three different methods for two spectral models, a power-law and APEC (see Smith et al., 2001, ApJL, 556, L91). Not all sources have values for all three methods. The parameters starting with "fix" are defined for every source and uses fixed spectral model parameters: a photon index of 1.7 for a power-law model, a temperature of kT=1keV for the APEC model and for both models uses the Galactic absorption listed in the parameter "nh". The parameters starting "intr" have been inferred from the hardness ratio. Look-up tables containing (HR1, HR2, NH, photon index) and (HR1, HR2, NH, kT) are pre-calculated for the power-law and APEC models. If the source HR1 and HR2 are close to the values in the table, spectral parameters are derived by interpolating the HR1 and HR2 in the look-up tables that are close to the HR1 and HR2 of the source. The parameters starting with "fit" have been derived from fitting an actual source spectrum in XSPEC and they are only available for the brightest sources (>50 net counts, and at least one detection in a single observation). The parameters fields starting with "pow" and "apec" report the values from the 'best' of these methods. The parameters "which_pow" and "which_apec" indicates which of the three methods are reported. The catalog also includes flags derived from the cross-correlated with other source catalogs. The catalogs and their reference sources are as follows: <pre> * AllWISE: <a href="https://wise2.ipac.caltech.edu/docs/release/allwise/">https://wise2.ipac.caltech.edu/docs/release/allwise/</a> * ROSAT HRI: <a href="https://heasarc.gsfc.nasa.gov/docs/rosat/rra/RRA.html">https://heasarc.gsfc.nasa.gov/docs/rosat/rra/RRA.html</a> * SDSS Quasar Catalog DR14: Paris et al., 2018, A&A, 613, 51 (<a href="https://www.sdss.org/dr14/algorithms/qso_catalog/">https://www.sdss.org/dr14/algorithms/qso_catalog/</a>) * 2MASS: Skrutskie et al., 2006, AJ, 131, 1163 * 2CSC: accessed via the CSCView Tool at <a href="https://cxc.harvard.edu/csc/about.html">https://cxc.harvard.edu/csc/about.html</a> (1CSC paper: Evans et al., 2010, ApJS, 189, 37) * 1SWXRT: Evans et al., 2014, ApJS, 210,8 * 1SXPS: D'Elia et al., 2013, A&A, 551, 142 * 2RXS: Boller et al., 2016, A&A, 588, 103 * 3XMM-DR8: <a href="http://xmmssc.irap.omp.eu/Catalogue/3XMM-DR8/3XMM_DR8.html">http://xmmssc.irap.omp.eu/Catalogue/3XMM-DR8/3XMM_DR8.html</a> (3XMM paper: Rosen, Webb, Watson et al., 2016, A&A, 590, 1) * 3XMM Stack: Traulsen et al., 2019, A&A, 642, 77 * SwiftFT: Puccetti et al. 2011, A&A,528, A122 * XMM SL2: Saxton et al., 2008, A&A 480, 611 * XRTGRB: Evans et al, 2009, MNRAS, 397, 1177 (<a href="https://www.swift.ac.uk/xrt_positions">https://www.swift.ac.uk/xrt_positions</a>) * USNOB1: Monet et al., 2003, AJ, 125, 984 </pre> The 2SXPS paper (Evans et al. 2020 ApJS, 247,54) describes in detail the methodology of stacking images, background modeling, point spread function mapping, stray light detection and corrections, data filtering techniques and processing. The 2SXPS catalog has a dedicated website at <a href="https://www.swift.ac.uk/2SXPS">https://www.swift.ac.uk/2SXPS</a>. This database table was created by the HEASARC in November 20201 based on the electronic version delivered to the HEASARC by the Leicester University. The catalog has a dedicated website at <a href="https://www.swift.ac.uk/2SXPS">https://www.swift.ac.uk/2SXPS</a>. The version available from the HEASARC corresponds to the catalog designated as "All" on the Leicester website. This is a service provided by NASA HEASARC .
