- ID:
- ivo://nasa.heasarc/swiftft
- Title:
- Swift Serendipitous Survey in Deep XRT GRB Fields (SwiftFT)
- Short Name:
- SWIFTFT
- Date:
- 09 May 2025
- 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 .
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- ID:
- ivo://nasa.heasarc/swsdssqso
- Title:
- Swift Simultaneous UV, Optical, and X-Ray Observed Quasar Catalog
- Short Name:
- SWSDSSQSO
- Date:
- 09 May 2025
- 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 .
21263. Swift TDRSS Messages
- ID:
- ivo://nasa.heasarc/swifttdrss
- Title:
- Swift TDRSS Messages
- Short Name:
- SWIFTTDRSS
- Date:
- 09 May 2025
- 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 .
- ID:
- ivo://nasa.heasarc/skyview/swiftuvot
- Title:
- Swift UVOT Combined V Intensity Images
- Short Name:
- SWIFTUVOT
- Date:
- 09 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Swift UVOT instrument is a 30 cm modified Ritchey-Chretien reflecting telescope launched on board the Swift satellite on November 20, 2004. The range of optical and UV filters can accomodate wavebands between 1700 and 6500 Angstroms. A full field image covers 17x17 arcminutes and at maximum spatial sampling is imaged onto 2048x2048 0.5" pixels. A 1000 second observation can detect point sources to m=22.3 when no filter is used. The Swift Serendipitous Source Catalog (Page et al., 2015) detects sources down to m=23-26 for the six filters in very deep observations, but the typical limits are substantially brighter (~20-23 magnitude). <p> These surveys are mosaics of all Swift UVOT observations released between the start of the mission and July 2017. Data were extracted from the HEASARC archive from the UVOT products directory. Mosaics are provided in six filters and also with no filter, i.e., WHITE. The table below gives the number of observations and bandpasses for each of the filters. For each UVOT observation standard processing generates a counts and exposure file as a single multi-extension FITS file with a separate extension for each filter. To aid processing, these extensions were copied into separate files in directory trees for each filter. Four observations in which the exposure and counts maps did not agree on the filters used were omitted from the processing. <p> Some observations were recorded with 0.5" pixels while others were binned to 1". All 0.5" observations (typically fewer than 10%) were rebinned to the larger pixels for the counts maps since the counts data scales with the pixel size. Since the exposure values are intensive and do not vary significantly based upon the resolution, these data were not generally rebinned unless it was needed to ensure that Order 9 Hips data were produced. <p> The CDS Hipsgen software was used to generate Order 9 HiPS data (~0.8" pixels) for both the Counts and Exposure images. The HiPS (Hierarchical Progressive Survey VO standard) supports multi-resolution mosaics. Any quantitative use of these images should note that the rebinning increases the total counts by a factor of ~(1.0/0.8)^2 ~ 1.56. This software uses a bilinear interpolation to generate HEALPix tiles of an appropriate order (18 in this case). <i>SkyView</i> developed software was used to divide the level 9 counts maps tiles by the corresponding exposure maps to create intensity tiles. Pixels where the exposure was less than 5 seconds were left as NaNs. The lower order (8 to 3) order intensity tiles were then generated by averaging 2x2 sets of the higher order maps treating any missing maps or pixels as NaNs. A HiPS all-sky image was generated by averaged the Order 3 tiles. <p> Only the Intensity HIPS files are presented in the SkyView web page directly, but intensity, counts and exposure maps are available for all seven filters. Note that unlike the XRT HiPS data, the exposure and counts maps have not been clipped. I.e., the source FITS files have been aligned with the coordinate system and thus contain large numbers of unexposed pixels with 0 values. These 0's are simply propogated to HiPS tiles. NaNs are returned in regions which lie outside any of the original source images. For the Intensity map, any pixel for which the exposure was less than 5s is returned as a NaN. <table border> <tr><th align=center>Filter</th><th>Count</th><th>Central Wavelength (&#8491;;)</th><th>Bandpass (&#8491;;)</th><th>Central Frequency(THz)</th><th>Bandpass (THz)</th><th>Coverage</th></tr> <tr><th align=center>WHITE</th><td align='center'>3,000</td><td align='center'>3600</td><td align='center'>1600-6000</td><td align='center'>832</td><td align='center'>500-1874</td> <td>0.0017</td></tr> <tr><th align=center>V</th><td align='center'>30,557</td><td align='center'>5468</td><td align='center'>5083-5852</td>< <td align='center'>548</td><td align='center'>512-590</td> <td>0.0171</td></tr> <tr><th align=center>B</th><td align='center'>28,347</td><td align='center'>4392</td><td align='center'>3904-4880</td> <td align='center'>683</td><td align='center'>614-768</td> <td>0.0112<td></tr> <tr><th align=center>U</th><td align='center'>49,954</td><td align='center'>3465</td><td align='center'>3072-3875</td> <td align='center'>865</td><td align='center'>774-975</td> <td>0.0287</td></tr> <tr><th align=center>UVW1</th><td align='center'>60,690</td><td align='center'>2600</td><td align='center'>2253-2946</td> <td align='center'>1154</td><td align='center'>1017-1330</td><td>0.0277</td></tr> <tr><th align=center>UVM2</th><td align='center'>56,977</td><td align='center'>2246</td><td align='center'>1997-2495</td> <td align='center'>1334</td><td align='center'>1201-1501</td>>td>0.0314</td></tr> <tr><th align=center>UVW2</th><td align='center'>54,590</td><td align='center'>1928</td><td align='center'>1600-2256</td> <td align='center'>1554</td><td align='center'>1328-1874</td><td>0.0260</td></tr> </table> <strong>Observation counts and bandpasses for UVOT Filters</strong> <p> Provenance: Data generated from public images at HEASARC archive. This is a service of NASA HEASARC.
21265. Swift UVOT Instrument Log
- ID:
- ivo://nasa.heasarc/swiftuvlog
- Title:
- Swift UVOT Instrument Log
- Short Name:
- SwiftUVOT
- Date:
- 09 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The UVOT runs only one type of configuration filter/mode/window in a given time interval. This database table, therefore, contains for a given time interval a single record that describes one configuration. This database table is generated by the Swift Data Center. During operation, it is updated on daily basis. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/ApJ/836/25
- Title:
- Swift UVOT light curves of ASASSN-15lh
- Short Name:
- J/ApJ/836/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the detection of persistent soft X-ray radiation with L_x_~10^41^-10^42^erg/s at the location of the extremely luminous, double-humped transient ASASSN-15lh as revealed by Chandra and Swift. We interpret this finding in the context of observations from our multiwavelength campaign, which revealed the presence of weak narrow nebular emission features from the host-galaxy nucleus and clear differences with respect to superluminous supernova optical spectra. Significant UV flux variability on short timescales detected at the time of the rebrightening disfavors the shock interaction scenario as the source of energy powering the long-lived UV emission, while deep radio limits exclude the presence of relativistic jets propagating into a low-density environment. We propose a model where the extreme luminosity and double-peaked temporal structure of ASASSN-15lh is powered by a central source of ionizing radiation that produces a sudden change in the ejecta opacity at later times. As a result, UV radiation can more easily escape, producing the second bump in the light curve. We discuss different interpretations for the intrinsic nature of the ionizing source. We conclude that, if the X-ray source is physically associated with the optical-UV transient, then ASASSN-15lh most likely represents the tidal disruption of a main-sequence star by the most massive spinning black hole detected to date. In this case, ASASSN-15lh and similar events discovered in the future would constitute the most direct probes of very massive, dormant, spinning, supermassive black holes in galaxies. Future monitoring of the X-rays may allow us to distinguish between the supernova hypothesis and the hypothesis of a tidal disruption event.
- ID:
- ivo://CDS.VizieR/J/ApJ/836/232
- Title:
- Swift-UVOT obs. analysis of 29 SNe Ia
- Short Name:
- J/ApJ/836/232
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The intrinsic colors of Type Ia supernovae (SNe Ia) are important to understanding their use as cosmological standard candles. Understanding the effects of reddening and redshift on the observed colors are complicated and dependent on the intrinsic spectrum, the filter curves, and the wavelength dependence of reddening. We present ultraviolet and optical data of a growing sample of SNe Ia observed with the Ultraviolet/Optical Telescope on the Swift spacecraft and use this sample to re-examine the near-UV (NUV) colors of SNe Ia. We find that a small amount of reddening (E(B-V)=0.2mag) could account for the difference between groups designated as NUV-blue and NUV-red, and a moderate amount of reddening (E(B-V)=0.5mag) could account for the whole NUV-optical differences. The reddening scenario, however, is inconsistent with the mid-UV colors and color evolution. The effect of redshift alone only accounts for part of the variation. Using a spectral template of SN2011fe, we can forward model the effects of redshift and reddening and directly compare those with the observed colors. We find that some SNe are consistent with reddened versions of SN2011fe, but most SNe Ia are much redder in the uvw1-v color than SN2011fe reddened to the same b-v color. The absolute magnitudes show that two out of five NUV-blue SNe Ia are blue because their near-UV luminosity is high, and the other three are optically fainter. We also show that SN 2011fe is not a "normal" SN Ia in the UV, but has colors placing it at the blue extreme of our sample.
- ID:
- ivo://CDS.VizieR/J/ApJ/897/18
- Title:
- Swift UVOT observation of the radio quasar 3C 273
- Short Name:
- J/ApJ/897/18
- Date:
- 16 Mar 2022 00:38:40
- Publisher:
- CDS
- Description:
- 3C273 is an intensively monitored flat-spectrum radio quasar with both a beamed jet and blue bump together with broad emission lines. The coexistence of the comparably prominent jet and accretion disk leads to complicated variability properties. Recent reverberation mapping monitoring for 3C273 revealed that the optical continuum shows a distinct long-term trend that does not have a corresponding echo in the H{beta} fluxes. We compile multiwavelength monitoring data from the Swift archive and other ground-based programs and clearly find two components of emissions at optical wavelength. One component stems from the accretion disk itself, and the other component can be ascribed to the jet contribution, which also naturally accounts for the nonechoed trend in reverberation mapping data. We develop an approach to decouple the optical emissions from the jet and accretion disk in 3C273 with the aid of multiwavelength monitoring data. By assuming that the disk emission has a negligible polarization in consideration of the low inclination of the jet, the results show that the jet contributes a fraction of ~10% at the minimum and up to ~40% at the maximum to the total optical emissions. This is the first time to provide a physical interpretation of the "detrending" manipulation conventionally adopted in reverberation mapping analysis. Our work also illustrates the importance of appropriately analyzing variability properties in cases of coexisting jets and accretion disks.
- ID:
- ivo://CDS.VizieR/J/ApJ/749/18
- Title:
- Swift/UVOT observations of 12 nearby SN-Ia
- Short Name:
- J/ApJ/749/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare early ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) with theoretical predictions for the brightness of the shock associated with the collision between SN ejecta and a companion star. Our simple method is independent of the intrinsic flux from the SN and treats the flux observed with the Swift/Ultra-Violet Optical Telescope as conservative upper limits on the shock brightness. Comparing this limit with the predicted flux for various shock models, we constrain the geometry of the SN progenitor-companion system. We find the model of a 1 M_{sun}_ red supergiant companion in Roche-lobe overflow to be excluded at a 95% confidence level for most individual SNe for all but the most unfavorable viewing angles. For the sample of 12 SNe taken together, the upper limits on the viewing angle are inconsistent with the expected distribution of viewing angles for red gaint stars as the majority of companions with high confidence. The separation distance constraints do allow main-sequence companions. A better understanding of the UV flux arising from the SN itself as well as continued UV observations of young SNe Ia will further constrain the possible progenitors of SNe Ia.
- ID:
- ivo://CDS.VizieR/J/ApJ/753/22
- Title:
- Swift/UVOT observations of SN 2011fe
- Short Name:
- J/ApJ/753/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the earliest ultraviolet (UV) observations of the bright Type Ia supernova SN 2011fe/PTF11kly in the nearby galaxy M101 at a distance of only 6.4 Mpc. It was discovered shortly after explosion by the Palomar Transient Factory and first observed by Swift/UVOT about a day after explosion. The early UV light is well defined, with ~20 data points per filter in the five days after explosion. These early and well-sampled UV observations form new template light curves for comparison with observations of other SNe Ia at low and high redshift. We report fits from semiempirical models of the explosion and find the time evolution of the early UV flux to be well fitted by the superposition of two parabolic curves. Finally, we use the early UV flux measurements to examine a possible shock interaction with a non-degenerate companion. From models predicting the measurable shock emission, we find that even a solar mass companion at a distance of a few solar radii is unlikely at more than 95% confidence.
