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21212. Swift Master Catalog
- ID:
- ivo://nasa.heasarc/swiftmastr
- Title:
- Swift Master Catalog
- Short Name:
- Swift
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table records high-level information for each Swift observation and provides access to the data archive. Each record is associated with a single observation that contains data from all instruments on board Swift. The BAT is the large field of view instrument and operates in the 10-300 keV energy band. The narrow field instruments, XRT and UVOT, operate in the X-ray and UV/optical regime, respectively. An observation is defined as a collection of snapshots, where a snapshot is defined as the time spent observing the same position continuously. Because of observing constraints, the length of a snapshot can be shorter than a single orbit and it can be interrupted because the satellite will point in a different direction of the sky or because the time allocated to that observation ends. The typical Swift observing strategy for a Gamma Ray Burst (GRB) and/or afterglow, consists of a serious of observations aimed at following the GRB and its afterglow evolution. This strategy is achieved with two different type of observations named Automatic Targets and Pre-Planned Targets. The Automatic Target is initiated on board soon after an event is triggered by the BAT. The Figure of Merit (FOM) algorithm, part of the observatory's autonomy, decides if it is worth requesting a slew maneuver to point the narrow field instruments (NFI) on Swift, XRT and UVOT, in the direction of the trigger. If the conditions to slew to the new position are satisfied, the Automatic Target observation takes place; all the instruments have a pre-set standard configuration of operating modes and filters and about 20000 seconds on source will be collected. The Pre-Planned Target observations instead are initiated from the ground once the trigger is known. These observations are planned on ground and uploaded onto the spacecraft. 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://CDS.VizieR/J/ApJ/854/66
- Title:
- Swift observations of Mrk 421. I. 2005-2008
- Short Name:
- J/ApJ/854/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present detailed results of Swift observations of the nearby TeV-detected blazar Mrk 421, based on the rich archival data obtained during 2005 March-2008 June. The best fits of the 0.3-10keV spectra were mainly obtained using the log-parabolic model, yielding low spectral curvatures expected in the case of the efficient stochastic acceleration of particles. During strong X-ray flares, the position of the synchrotron spectral energy distribution peak E_p_ was beyond 8keV for 41 spectra, while it sometimes was situated at the UV frequencies in quiescent states. The photon index at 1 keV exhibited a broad range, and the values a<1.70 were observed during the strong flares, hinting at the possible presence of a jet hadronic component. The spectral parameters were correlated in some periods, expected in the framework of the first- and second-order Fermi accelerations of X-ray emitting particles, as well as in the case of turbulence spectrum. The 0.3-10keV flux and spectral parameters sometimes showed very fast variability down to the fluctuations by 6-20% in 180-960s, possibly related to the small-scale turbulent areas containing strongest magnetic fields. X-ray and very high-energy fluxes often showed correlated variability, although several occurrences of more complicated variability patterns are also revealed, indicating that the multifrequency emission of Mrk 421 could not be generated in a single zone.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/27
- Title:
- Swift obs. of Mrk 421. III. 2015 Dec-2018 Apr
- Short Name:
- J/ApJS/247/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from the timing and spectral study of Mrk 421 based mainly on the Swift data in the X-ray energy range obtained during the time interval 2015 December-2018 April. The most extreme X-ray flaring activity on long-term, daily, and intraday timescales was observed during the 2 month period that started in 2017 December, when the 0.3-10keV flux exceeded a level of 5x10^-9^erg/cm^2^/s, recorded only twice previously. While the TeV- band and X-ray variabilities were mostly correlated, the source often varied in a complex manner in the MeV-GeV and radio-UV energy ranges, indicating that the multifrequency emission of Mrk 421 could not always be generated in a single zone. The longer-term flares at X-rays and {gamma}-rays showed a lognormal character, possibly indicating a variability imprint of the accretion disk onto the jet. A vast majority of the 0.3-10keV spectra were consistent with the log-parabolic model, showing relatively low spectral curvature and correlations between the different spectral parameters, predicted in the case of the first- and second-order Fermi processes. The position of the synchrotron spectral energy distribution peak showed an extreme variability on diverse timescales between the energies Ep<0.1 and >15keV, with 15% of the spectra peaking at the hard X-ray, and was related to the peak height as S^p^{propto}E_p_^{alpha}^ with {alpha}~0.6, which is expected for the transition from Kraichnan-type turbulence into the "hard sphere" one. The 0.3-300GeV spectra showed features of the hadronic contribution, jet-star interaction, and upscatter in the Klein-Nishina regime in different time intervals.
- ID:
- ivo://CDS.VizieR/J/ApJ/858/68
- Title:
- Swift obs. of Mrk 421 in selected epochs. II.
- Short Name:
- J/ApJ/858/68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from a detailed spectral and timing study of Mrk 421 based on the rich archival Swift data obtained during 2009-2012. Best fits of the 0.3-10keV spectra were mostly obtained using the log-parabolic model showing the relatively low spectral curvature that is expected in the case of efficient stochastic acceleration of particles. The position of the synchrotron spectral energy density peak E_p_ of 173 spectra is found at energies higher than 2keV. The photon index at 1 keV exhibited a very broad range of values a=1.51-3.02, and very hard spectra with a<1.7 were observed during the strong X-ray flares, hinting at a possible hadronic jet component. The spectral parameters varied on diverse timescales and showed a correlation in some periods, which is expected in the case of first- and second-order Fermi acceleration. The 0.3-10keV flux showed strong X-ray flaring activity by a factor of 3-17 on timescales of a few days-weeks between the lowest historical state and that corresponding to a rate higher than 100ct/s. Moreover, 113 instances of intraday variability were revealed, exhibiting shortest flux-doubling/halving times of about 1.2hr, as well as brightenings by 7%-24% in 180-720 s and declines by 68%-22% in 180-900s. The X-ray and very high-energy fluxes generally showed a correlated variability, although one incidence of a more complicated variability was also detected, indicating that the multifrequency emission of Mrk 421 could not be generated in a single zone.
- ID:
- ivo://CDS.VizieR/J/ApJ/828/3
- Title:
- Swift obs. of the superluminous SNI ASASSN-15lh
- Short Name:
- J/ApJ/828/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and discuss ultraviolet and optical photometry from the Ultraviolet/Optical Telescope, X-ray limits from the X-Ray Telescope on Swift, and imaging polarimetry and ultraviolet/optical spectroscopy with the Hubble Space Telescope, all from observations of ASASSN-15lh. It has been classified as a hydrogen-poor superluminous supernova (SLSN I), making it more luminous than any other supernova observed. ASASSN-15lh is not detected in the X-rays in individual or co-added observations. From the polarimetry we determine that the explosion was only mildly asymmetric. We find the flux of ASASSN-15lh to increase strongly into the ultraviolet, with an ultraviolet luminosity 100 times greater than the hydrogen-rich, ultraviolet-bright SLSN II SN 2008es. We find that objects as bright as ASASSN-15lh are easily detectable beyond redshifts of ~4 with the single-visit depths planned for the Large Synoptic Survey Telescope. Deep near-infrared surveys could detect such objects past a redshift of ~20, enabling a probe of the earliest star formation. A late rebrightening-most prominent at shorter wavelengths-is seen about two months after the peak brightness, which is itself as bright as an SLSN. The ultraviolet spectra during the rebrightening are dominated by the continuum without the broad absorption or emission lines seen in SLSNe or tidal disruption events (TDEs) and the early optical spectra of ASASSN-15lh. Our spectra show no strong hydrogen emission, showing only Ly{alpha} absorption near the redshift previously found by optical absorption lines of the presumed host. The properties of ASASSN-15lh are extreme when compared to either SLSNe or TDEs.
- ID:
- ivo://CDS.VizieR/J/ApJ/870/123
- Title:
- Swift optical & UV flux of four AGNs
- Short Name:
- J/ApJ/870/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Swift intensive accretion disk reverberation mapping of four AGN yielded light curves sampled ~200-350 times in 0.3-10keV X-ray and six UV/optical bands. Uniform reduction and cross-correlation analysis of these data sets yields three main results: (1) The X-ray/UV correlations are much weaker than those within the UV/optical, posing severe problems for the lamp-post reprocessing model in which variations in a central X-ray corona drive and power those in the surrounding accretion disk. (2) The UV/optical interband lags are generally consistent with {tau}{propto}{lambda}^4/3^ as predicted by the centrally illuminated thin accretion disk model. While the average interband lags are somewhat larger than predicted, these results alone are not inconsistent with the thin disk model given the large systematic uncertainties involved. (3) The one exception is the U band lags, which are on average a factor of ~2.2 larger than predicted from the surrounding band data and fits. This excess appears to be due to diffuse continuum emission from the broad-line region (BLR). The precise mixing of disk and BLR components cannot be determined from these data alone. The lags in different AGN appear to scale with mass or luminosity. We also find that there are systematic differences between the uncertainties derived by Just Another Vehicle for Estimating Lags In Nuclei (JAVELIN) versus more standard lag measurement techniques, with JAVELIN reporting smaller uncertainties by a factor of 2.5 on average. In order to be conservative only standard techniques were used in the analyses reported herein.
- ID:
- ivo://nasa.heasarc/swiftft
- Title:
- Swift Serendipitous Survey in Deep XRT GRB Fields (SwiftFT)
- Short Name:
- SWIFTFT
- Date:
- 27 Sep 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/swsdssqso
- Title:
- Swift Simultaneous UV, Optical, and X-Ray Observed Quasar Catalog
- Short Name:
- SWSDSSQSO
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have compiled a catalog of optically selected quasars with simultaneous observations in UV/optical and X-ray bands by the Swift Gamma-ray Burst Explorer. Objects in this catalog are identified by matching the Swift pointings with the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasar catalog. The final catalog contains 843 objects, among which 637 have both Ultraviolet Optical Telescope (UVOT) and X-Ray Telescope (XRT) observations and 354 of which are detected by both instruments. The overall X-ray detection rate is ~ 60% which rises to ~ 85% among sources with at least 10 ks of XRT exposure time. The authors construct the time-averaged spectral energy distribution (SED) for each of the 354 quasars using UVOT photometric measurements and XRT spectra. From model fits to these SEDs, they find that the big blue bump contributes about ~ 0.3 dex to the quasar luminosity. The authors re-visit the alpha<sub>ox</sub> - L<sub>2500A</sub> relation by selecting a clean sample with only Type 1 radio-quiet quasars; the dispersion of this relation is reduced by at least 15% compared with studies that use non-simultaneous UV/optical and X-ray data. They find only a weak correlation between L<sub>bol</sub>/L<sub>Edd</sub> and alpha<sub>UV</sub>. They do not find significant correlations between alpha<sub>x</sub> and alpha<sub>ox</sub>, alpha<sub>ox</sub> and alpha<sub>UV</sub>, and alpha<sub>x</sub> and log L(0.3-10 keV). The correlations between alpha<sub>UV</sub> and alpha<sub>x</sub>, alpha<sub>ox</sub> and alpha<sub>x</sub>, alpha<sub>ox</sub> and alpha<sub>UV</sub>, L<sub>bol</sub>/L<sub>Edd</sub> and alpha<sub>x</sub>, and L<sub>bol</sub>/L<sub>Edd</sub> and alpha<sub>ox</sub> are stronger among low-redshift quasars, indicating that these correlations are likely driven by the changes of SED shape with accretion state. This quasar sample was compiled in the following steps: 1. Candidate objects for the catalog were selected as any SDSS DR5 quasar that lie within 20 arcminutes of the center of the Swift FOV in any pointing from launch through 2008 June. 2. XRT data were processed to obtain X-ray count rates, spectra, and spectral parameters. 3. UVOT data were processed to obtain UV and optical photometry. 4. UVOT photometry were supplemented with measurements at other wavelengths from published catalogs. 5. Quasar SEDs were constructed. 6. Additional parameters were calculated based on the SEDs of each quasar. The raw sample is constructed by matching 3.5 years Swift pointings and the SDSS DR5 quasar catalog and contains 1034 objects. This HEASARC version of this catalog contains all 1034 objects in the "raw" catalog. To select only the 843 objects in the "final" catalog, the user should specify catalog_flag = 1 in any searches of this table. This table was created by the HEASARC in August 2012 based on an electronic version of Table 8 from the reference paper which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .
21220. Swift TDRSS Messages
- ID:
- ivo://nasa.heasarc/swifttdrss
- Title:
- Swift TDRSS Messages
- Short Name:
- SWIFTTDRSS
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table is derived from the Swift TDRSS messages sent on ground soon after a BAT trigger occurs on-board. For each trigger there are associated up to 14 messages, however not all are always generated and sent on ground. The messages are generated on board by the BAT, XRT and UVOT instruments and the Figure of Merit part of the observatory's autonomy. The BAT and XRT can each have five different message types. The UVOT and FOM can each have two different message types. These TDRSS messages are the results of the on-board data processing of the three instruments and some contain data products. They are first distributed via the GCN and later archived. The BAT messages are: alert, 'ack' containing the position, or 'nack' if the position could not be calculated, a lightcurve and scaled map. The XRT messages are: centroid containing the position, an image (if the position has been calculated), centroid error if the position could not be calculated, spectra in Low Rate Photodiode and Windowed Timing modes, a lightcurve. The UVOT messages are: finding chart containing star positions and a subimage centered on the XRT position. The FOM messages are used to indicate if the FOM will or will not observe the new target and if the spacecraft will (or will not) request a slew for the new target. The parameters in this database table are a collection of high level information taken from the following messages : the BAT alert, 'ack' or 'nack' message, the FOM messages, the XRT position and image. If the information is not available the fields are left blank. All messages are provided as data products within this database table. 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 .