- ID:
- ivo://nasa.heasarc/sacsspscat
- Title:
- SwiftAGN&ClusterSurvey(SACS)Soft-Band(0.5-2keV)PointSourceCatalog
- Short Name:
- SACSSPSCAT
- Date:
- 09 May 2025
- 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 .
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- ID:
- ivo://nasa.heasarc/sacstpscat
- Title:
- SwiftAGN&ClusterSurvey(SACS)Total-Band(0.2-10keV)PointSourceCatalog
- Short Name:
- SACSTPSCAT
- Date:
- 09 May 2025
- 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://CDS.VizieR/J/ApJ/831/102
- Title:
- Swift and NuSTAR obs. of the BL Lac Mrk 421
- Short Name:
- J/ApJ/831/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the Swift and NuSTAR observations of the nearby BL Lac object Mrk 421 during 2013 January-June. The source exhibited a strong long-term variability in the 0.3-10keV and 3-79keV bands with the maximum-to-minimum daily-binned flux ratios of 22 and 95, respectively, in about 3 months, mainly due to unprecedented strong X-ray outbursts by more than an order of magnitude in both bands within 2 weeks in 2013 April when the 0.3-10keV count rate exceeded the level of 200cts/s for the first time, and Mrk 421 became one of the brightest sources in the X-ray sky. The source was also very active on intra-day timescales, and it showed flux doubling and halving timescales of 1.16-7.20hr and 1.04-3.54hr, respectively. On some occasions, the flux varied by 4%-23% within 300-840s. During this period, the source also exhibited some of the most extreme X-ray spectral variability ever reported for BL Lacs-the location of the synchrotron spectral energy distribution peak shifted from a few eV to ~10keV, and the photon index at 1 keV and curvature parameter varied on timescales from a few weeks down to intervals shorter than 1ks. MAGIC and First G-APD Cherenkov Telescope observations also revealed a very strong very high energy (VHE) flare during April 11-17. The UV and HE {gamma}-ray flares were much weaker compared to their X-ray counterparts, and they generally showed significantly stronger correlation with each other than with the X-ray fluxes.
- ID:
- ivo://CDS.VizieR/J/ApJ/850/74
- Title:
- Swift/BAT AGN Spectroscopic Survey. I.
- Short Name:
- J/ApJ/850/74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first catalog and data release of the Swift-BAT AGN Spectroscopic Survey. We analyze optical spectra of the majority of the detected AGNs (77%, 642/836) based on their 14-195keV emission in the 70-month Swift-BAT all-sky catalog. This includes redshift determination, absorption and emission-line measurements, and black hole mass and accretion rate estimates for the majority of obscured and unobscured AGNs (74%, 473/642), with 340 measured for the first time. With ~90% of sources at z<0.2, the survey represents a significant advance in the census of hard X-ray-selected AGNs in the local universe. In this first catalog paper, we describe the spectroscopic observations and data sets, and our initial spectral analysis. The FWHMs of the emission lines show broad agreement with the X-ray obscuration (~94%), such that Sy 1-1.8 have N_H_<10^21.9^cm^-2^, and Seyfert 2 have N_H_>10^21.9^cm^-2^. Seyfert 1.9, however, show a range of column densities. Compared to narrow-line AGNs in the SDSS, the X-ray-selected AGNs have a larger fraction of dusty host galaxies (H{alpha}/H{beta}>5), suggesting that these types of AGN are missed in optical surveys. Using the [OIII]{lambda}5007/H{beta} and [NII]{lambda}6583/H{alpha} emission-line diagnostic, about half of the sources are classified as Seyferts; ~15% reside in dusty galaxies that lack an H{beta} detection, but for which the upper limits on line emission imply either a Seyfert or LINER, ~15% are in galaxies with weak or no emission lines despite high-quality spectra, and a few percent each are LINERS, composite galaxies, H II regions, or in known beamed AGNs.
- ID:
- ivo://CDS.VizieR/J/ApJS/233/17
- Title:
- Swift/BAT AGN spectroscopic survey. V. X-ray data
- Short Name:
- J/ApJS/233/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hard X-ray (>=10keV) observations of active galactic nuclei (AGNs) can shed light on some of the most obscured episodes of accretion onto supermassive black holes. The 70-month Swift/BAT all-sky survey, which probes the 14-195keV energy range, has currently detected 838 AGNs. We report here on the broadband X-ray (0.3-150keV) characteristics of these AGNs, obtained by combining XMM-Newton, Swift/XRT, ASCA, Chandra, and Suzaku observations in the soft X-ray band (<=10keV) with 70-month averaged Swift/BAT data. The nonblazar AGNs of our sample are almost equally divided into unobscured (N_H_<10^22^cm^-2^) and obscured (N_H_>=10^22^cm^-2^) AGNs, and their Swift/BAT continuum is systematically steeper than the 0.3-10keV emission, which suggests that the presence of a high-energy cutoff is almost ubiquitous. We discuss the main X-ray spectral parameters obtained, such as the photon index, the reflection parameter, the energy of the cutoff, neutral and ionized absorbers, and the soft excess for both obscured and unobscured AGNs.
21226. SWIFT/BAT detections of AGN
- ID:
- ivo://CDS.VizieR/J/ApJ/633/L77
- Title:
- SWIFT/BAT detections of AGN
- Short Name:
- J/ApJ/633/L77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present preliminary results from the first 3 months of the Swift Burst Alert Telescope (BAT) high Galactic latitude survey in the 14-195keV band. The survey reaches a flux of ~10^-11^erg/cm^2^/s and has ~2.7' (90% confidence) positional uncertainties for the faintest sources. This represents the most sensitive survey to date in this energy band. These data confirm the conjectures that a high-energy-selected active galactic nucleus (AGN) sample would have very different properties from those selected in other bands and that it represents a "true" sample of the AGN population. We have identified 86% of the 66 high-latitude sources. Twelve are Galactic-type sources, and 44 can be identified with previously known AGNs.
- ID:
- ivo://CDS.VizieR/J/ApJ/896/L20
- Title:
- Swift BAT gamma-ray burst durations
- Short Name:
- J/ApJ/896/L20
- Date:
- 21 Mar 2022 07:00:25
- Publisher:
- CDS
- Description:
- The duration of a gamma-ray burst (GRB) is a key indicator of its physical origin, with long bursts perhaps associated with the collapse of massive stars and short bursts with mergers of neutron stars. However, there is substantial overlap in the properties of both short and long GRBs and neither duration nor any other parameter so far considered completely separates the two groups. Here we unambiguously classify every GRB using a machine-learning dimensionality reduction algorithm, t-distributed stochastic neighborhood embedding, providing a catalog separating all Swift GRBs into two groups. Although the classification takes place only using prompt emission light curves, every burst with an associated supernova is found in the longer group and bursts with kilonovae in the short, suggesting along with the duration distributions that these two groups are truly long and short GRBs. Two bursts with a clear absence of a supernova belong to the longer class, indicating that these might have been direct-collapse black holes, a proposed phenomenon that may occur in the deaths of more massive stars.
21228. Swift BAT Instrument Log
- ID:
- ivo://nasa.heasarc/swiftbalog
- Title:
- Swift BAT Instrument Log
- Short Name:
- SwiftBAT
- Date:
- 09 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The BAT can operate several configuration modes simultaneously. Each of the simultaneous modes is listed in separate records within this table. For a given time interval, there are several records (partially overlapping in time), each describing a single configuration/mode. The BAT modes collect data for the entire FOV but also have the capability to record rates (tag mask rate) for up to a few specific sky positions (typically 3) that correspond to a pre-assigned target ID. It is possible that at least two or more of these positions do not coincide with the BAT or NFI pointing position and therefore the target ID does necessarily coincide with Target_ID of the BAT or NFI pointing position. This table records for the position (RA and Dec) and Target_ID parameters the correct values associated to each of the mask tag data. This database table is generated at the Swift processing site. During operation, it is updated on daily basis. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/swbat157m
- Title:
- Swift-BAT 157-Month All-Sky Hard X-Ray Survey
- Short Name:
- SWBAT157M
- Date:
- 09 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog includes the hard X-ray sources detected in the first 157 months of observations with the Burst Alert Telescope (BAT) coded-mask imager on board the Swift observatory. The results of the 157 months survey catalog has been obtained using data from February 2007 to December 2017 and provide a uniform hard X-ray all-sky survey with a sensitivity of 8.40 x 10<sup>-12</sup> erg/s/cm<sup>2</sup> over 90% of the sky and 7.24 x 10<sup>-12</sup> erg/s/cm<sup>2</sup> over 50% of the sky in the 14-195 keV band. The exposure time in all sky ranges from ~ 15 Ms to ~ 35 Ms, where ~ 50% of the sky achieves an exposure time of ~ 22.8 Ms. The 157 months survey provides 1891 hard X-ray sources in the 14-195 keV band above the 4.8 sigma significance level, where 259 are new detections from the 105-month catalog of which 54 are previously known source in X-ray. The sources identification is mostly from NED and SIMBAD and the 157-month catalog reports for positive identification the counterpart R.A. and Dec and the alternative name. The sources are classified in 17 different classes as follows: <pre> Class Source Type Number of Sources 0 Unknown 221 1 Galactic 4 2 Galaxy 16 3 Galaxy Cluster 26 4 Seyfert I 446 5 Seyfert II 464 6 Other AGN 130 7 Beamed AGN (Blazar/FSRQ) 192 8 LINER 7 9 Cataclysmic Variable Star (CV) 81 10 Pulsar 27 11 Supernova Remnant (SNR) 7 12 Star 26 13 High Mass X-ray Binary (HMXB) 108 14 Low Mass X-ray Binary (LMXB) 118 15 Other X-ray Binary (XRB) 17 16 Tidal Disruption Event 1 Total 1891 </pre> The data reduction, analysis, and catalog generation of the Swift-BAT are conducted following the same procedures of the previous catalog survey (Tueller+ 2010, J/ApJS/1167/186, Baumgartner+ 2013, J/ApJS/207/19). The BAT survey data are collected into arrays (Detector Plane Histograms, DPHs) where the data are binned in ~ 300 s time interval and in 8 energy band channels (14-20, 20-24, 24-35, 35-50, 50-75, 75-100, 100- 197 150, and 150-195 keV) and 1 energy total band (14-195 keV). Three different mosaic images are created from the DPH dividing the sky in 6 regions. The first set has images created in 8 energy bands to span a contiguous time interval (snapshot). The second set has images co-adding data on a time period of a month. The third set is created in 8 energy bands by Crab-weighting the monthly images in each of the energy band with the following weights (Baumgartner+ 2013, J/ApJS/207/19): 27.000, 35.260, 22.700, 29.444, 21.272, 16.062, 8.449, 2.630. The benchmark Crab spectrum adopted is F(E) = 10.17E−2.15 photon cm2 s keV. The source detection algorithm uses the Crab-weighted mosaic images. For each source detected lightcurves and spectra are derived. The lightcurves are obtained from the snapshot images, the mosaic monthly images and the Crab-weighted mosaic images. The spectra are obtained from an additional set of mosaic images by adding all the snapshots for the 157 months period in 8-bands. All the analyses use HEASoft tools version 6.23, and the most recent BAT calibration database (updated on Oct. 3, 2017). Data products are generated for each source detected and these are: three different lightcurves in FITS format obtained from the snapshot, monthly and Crab-weighted monthly mosaic images and the equivalent plots as GIF images; an 8-channel average spectrum in FITS obtained using all 157 months; and a GIF file showing the spectrum with the fit to the best parameter of the power-law model. The snapshot lightcurves report rates for the 8-energy band, the monthly and Crab-weighted monthly mosaic lightcurves reports rated for the 8-energy band and the total band 14-195 keV. This table was ingested by the HEASARC in February 2025 based upon the published 157-month catalog. The catalog is also available at <a href="https://swift.gsfc.nasa.gov/results/bs157mon/">https://swift.gsfc.nasa.gov/results/bs157mon/</a>. 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:
- 09 May 2025
- 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 .
