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:

 Data included 2005 Jan 01 - 2018 August 01 Sky coverage 3,790 square degrees Typical Sensitivity (0.3-10 keV) 2x10-13 erg cm-2 s-1 (observations) 4x10-14 erg cm-2 s-1 (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% 

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:

 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 

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

Surveys above 10 keV represent one of the best resources to provide an unbiased census of the population of active galactic nuclei (AGNs). The authors present the results of 60 months of observation from 2005 March to 2010 March of the hard X-ray sky with the Swift Burst Alert Telescope (BAT). In this time frame, BAT detected (in the 15 - 55 keV band) 720 sources with a signal-to-noise ratio of >= 5 sigma in an all-sky survey, of which 428 are associated with AGNs, most of which are nearby. This sample has negligible incompleteness and statistics which are a factor of ~ 2 larger over similarly complete sets of AGNs. The sample contains (at least) 15 bona fide Compton-thick AGNs and 3 likely candidates. Compton-thick AGNs represent ~ 5% of AGN samples detected above 15 keV. The authors use the BAT data set to refine the determination of the log N - log S of AGNs which is extremely important, now that NuSTAR prepares for launch, toward assessing the AGN contribution to the cosmic X-ray background. The authors show that the log N - log S of AGNs selected above 10 keV is now established to ~ 10% precision. They derive the luminosity function of Compton-thick AGNs and measure a space density of 7.9 (+4.1, -2.9) x 10^-5 Mpc^-3 for objects with a de-absorbed luminosity larger than 2 x 10⁴² erg s^-1. As the BAT AGNs are all mostly local, they allow us to investigate the spatial distribution of AGNs in the nearby universe regardless of absorption. The authors find concentrations of AGNs that coincide spatially with the largest congregations of matter in the local (<= 85 Mpc) universe. There is some evidence that the fraction of Seyfert 2 objects is larger than average in the direction of these dense regions. This table was created by the HEASARC in May 2012, based on an electronic version of Table 1 from the referenced paper, which was obtained from the ApJ website. This is a service provided by NASA HEASARC .

The SWBATMONTR database table records high-level information of the lightcurves from the sources monitored with the Burst Alert Telescope (BAT) on board of Swift. The Swift/BAT Monitoring Program is aimed at (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of lightcurves of more than 1000 sources spanning the entire Swift lifetime. 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 BAT monitoring the sky in the field of view and provides alerts when detecting a burst of flux coming from a source in the field of view. The BAT monitoring lightcurves are generated by the BAT team over the course of the Swift mission. The HEASARC ingests these data in the archive and generates this database table by collecting high-level information from the data. The lightcurves are renamed to use a consistent naming convention, and the FITS header is updated by adding standard FITS keywords. This is a service provided by NASA HEASARC .

This table contains the Swift X-ray Cluster Survey (SWXCS) catalog obtained using archival data from the X-ray telescope (XRT) on board the Swift satellite acquired from 2005 February to 2012 November, extending the first release of the SWXCS. The catalog provides positions and soft X-ray fluxes for a flux-limited sample of X-ray group and cluster candidates. In Table 3 of the reference paper (available at the HEASARC as the linked table SWXCSOXID), when possible, optical counterparts are given for these candidates. The authors consider the fields with Galactic latitude |b| > 20 degrees so as to avoid regions of high H I column density. They discard all of the observations targeted at groups or clusters of galaxies, as well as particular extragalactic fields not suitable for searching for faint extended sources. The authors finally select ~ 3000 useful fields covering a total solid angle of ~ 400 deg². They identify extended source candidates in the soft-band (0.5-2 keV) images of these fields using the software EXSdetect, which is specifically calibrated for the XRT data. Extensive simulations are used to evaluate contamination and completeness as a function of the source signal, allowing the authors to minimize the number of spurious detections and to robustly assess the selection function. The final catalog includes 263 candidate galaxy clusters and groups down to a flux limit of 7 x 10^-15 erg/cm²/s in the soft band (0.5 - 2.0 keV), and the log N - log S is in very good agreement with previous deep X-ray surveys. In the reference paper, the final list of sources is cross-correlated with published optical, X-ray, and Sunyaev-Zel'dovich catalogs of clusters. The authors find that 137 sources have been previously identified as clusters in the literature in independent surveys, while 126 are new detections. Currently, they have collected redshift information for 158 sources (60% of the entire sample). From the entire Swift XRT archive in the period 2005 February-2012 November, the authors have selected all the fields that can be used to build an unbiased, serendipitous X-ray cluster catalog. This table was created by the HEASARC in March 2015 based on an electronic version of Table 2 from the reference paper which was obtained from the CDS as their catalog J/ApJS/216/28 file table2.dat. This is a service provided by NASA HEASARC .

The authors have constructed a uniform all-sky survey of bright blazars, selected primarily by their flat radio spectra, that is designed to provide a large catalog of likely gamma-ray active galactic nuclei (AGNs). The defined sample, the Candidate Gamma-Ray Blazar Survey (CGRaBS) source catalog, has 1625 targets with radio and X-ray properties similar to those of the EGRET blazars, spread uniformly across the |b| > 10 degrees sky. They also report progress toward optical characterization of the sample; of objects with known red magnitude R < 23, 85% have been classified and 81% have measured redshifts. One goal of this program is to focus attention on the most interesting (e.g., high-redshift, high-luminosity, etc.) sources for intensive multi-wavelength study during the observations by the Large Area Telescope (LAT) on the Gamma-Ray Large-Area Space Telescope (GLAST) satellite observatory. This table was created by the HEASARC in April 2008 based on an electronic version of Table 2 of the reference paper obtained from the electronic ApJS web site. This is a service provided by NASA HEASARC .