- ID:
- ivo://nasa.heasarc/swiftuvlog
- Title:
- Swift UVOT Instrument Log
- Short Name:
- SwiftUVOT
- Date:
- 07 Mar 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 .
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- ID:
- ivo://nasa.heasarc/skyview/swiftxrt
- Title:
- Swift XRT Combined Intensity Images
- Short Name:
- SWIFTXRT
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Swift XRT (<a href="https://ads.harvard.edu/abs/2005SSRv..120..165B">Burrows et al 2005, SSRv, 120, 165</a>) is a sensitive, broad-band (0.2 - 10 keV) X-ray imager with an effective area of about 125 cm**2 at 1.5 keV. The 600 x 600 pixel CCD at the focus provides a 23.6' x 23.6' field of view with a pixel scale of 2.36". The point spread function is 18" (HPD) at 1.5 keV. <p> These XRT surveys represent the data from the first 12.5 years of Swift X-ray observations. They include all data taken in photon counting mode. A total of just over 8% of the sky has some non-zero exposure. The fraction of sky exposed as a function of the exposure is given in the following table: <table border> <tr><th>Exposure</th><td>>0</td> <td>10</td> <td>30</td> <td>100</td> <td>300</td> <td>1000</td> <td>3000</td> <td>1000</td> <td>30000</td> <td>100000</td><td>300000</td></tr> <tr><th>Coverage</th> <td> 8.42 </td><td> 8.37 </td><td> 8.29 </td><td> 7.67 </td><td> 7.29 </td><td> 5.68 </td> <td> 3.40 </td><td> 1.26 </td><td> 0.35 </td><td> 0.044 </td><td> 0.00118</td></th> </table> The individual exposure and counts maps have been combined into a Hierarchical Progressive Survey (HiPS) where the data are stored in tiles in the HEALPix projection at a number of different resulutions. The highest resolution pixels (HEALPix order 17) have a size of roughly 1.6". Data are also stored at lower resolutions at factors of 1/2, 1/4, 1/8, 1/16, and 1/32, and in an all sky image with a resolution 1/256 of the higest resolution. An intensity map has been created as the ratio of the counts and exposure maps. <p> These surveys combine the basic count and exposure maps provided as standard products in the Swift XRT archive in obsid/xrt/products/*xpc_(sk|ex).img.gz. The surveys were created as follows: <ul> <li>All of the exposure maps available in the archive in mid-May 2017 were combined using the CDS-developed Hipsgen tool. This includes 129,063 observations for which both count and exposure files were found in PC mode. Three exposures where there was a counts map but no exposure map were ignored. A few exposure files had more than one exposure extension. 1,082 files had two extensions and 1 file had 3 extensions. The 1084 HDUs in extensions were extracted as separate files and included in the total exposure. The value of 0 was given to the Hipsgen software as the null value for the FITS files. This caused the CDS software to treat such pixels as missing rather than 0 exposure. <li> The counts data was extracted from the counts maps for each observation using <i>SkyView</i> developed software. For any pixel in which a count was recorded, the corresponding exposure file was checked and if there was any exposure (in any of the associated extensions), then the count was retained. If there was no exposure in any of the extensions of the corresponding exposure file, the counts in the pixel were omitted. Once a count was accepted, the overlap between the counts map pixel and the pixels of the corresponding HiPS tile (or tiles) was computed. Each count was then assigned entirely to a single pixel in the HiPS tile randomly but with the destination pixel probabilities weighted by area of the overlap. Thus if several pixels were found in a given counts map pixel they might be assigned to different pixels in the output image. The HiPS pixels (~1.6") used were of substantially higher resolution than the XRT resolution of 18" and somewhat higher than the counts map resolution of 2.36". <p> A total of 183,750,428 photons were extracted from the counts maps while 15,226 were rejected as being from pixels with 0 exposure. There were 501 pixels which required special treatment as straddling the boundaries of the HEALPix projection. <li> The resulting counts tiles were then clipped using the exposure tiles that had been previously generated. Basically this transferred the coverage of the exposure tiles to the counts tiles. Any counts pixel where the corresponding exposure pixel was a NaN was changed to a NaN to indicate that there was no coverage in this region. <p> During the clipping process 137,730 HiPS level 8 were clipped (of 786,432 over the entire sky). There were 12,236 tiles for which there was some exposure but no counts found. During the clipping process 2 photons were found on pixels where there was no corresponding exposure in the exposure tiles. This can happen when the pixel assignment process noted above shifts a photon just outside the exposed region but should be -- as it was -- rare. These photons were deleted. <li> After creating the clipped level 8 counts maps, level 7 to 3 tiles and an all sky map where generated by averaging pixels 2x2 to decrease each level. When adding the four pixels in the level N map together only pixels whose value was not NaN were considered. <li> Finally an intensity map was created by dividing the counts tiles by the exposure tiles. To eliminate gross fluctuations due to rare counts in regions with very low exposure, only regions with exposure > 1 second were retained. A total of 30 photons were deleted due to this criterion. </ul> <p> Note that while any sampler may in principle be used with these data, the Spline sampler may give unexpected results. The spline computation propogates NaNs thought the image and means that even occasional NaNs can corrupt the output image completely. NaNs are very common in this dataset. Also, if the region straddles a boundary in the HEALPix projection, the size of the requested input region is likely to exceed memory limits since the HiPS data are considered a single very large image. Provenance: Data generated from public images at HEASARC archive. This is a service of NASA HEASARC.
- ID:
- ivo://nasa.heasarc/swiftxrlog
- Title:
- Swift XRT Instrument Log
- Short Name:
- SwiftXRT
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The XRT runs only one type of configuration mode/window in a given time interval. The table therefore contains for a given time interval a single record that describes one configuration. A new record is generated when the following is changing within an observation: new operating mode , new pointing mode, or new window 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://nasa.heasarc/skyview/sumss
- Title:
- Sydney University Molonglo Sky Survey
- Short Name:
- SUMSS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Sydney University Molonglo Sky Survey (SUMSS) is a deep radio survey at 843 MHz of the entire sky south of declination -30&#176;;, made using the Molonglo Observatory Synthesis Telescope (<a href="https://www.physics.usyd.edu.au/astrop/most/"> MOST </a>), located near Canberra, Australia. The images from the SUMSS are produced as 4 x 4 degree mosaics of up to seventeen individual observations, to ensure even sensitivity across the sky. The mosaics slightly overlap each other. Data were last updated on January 28, 2015. <p> Images can also be obtained from the <a href="https://www.astrop.physics.usyd.edu.au/cgi-bin/postage.pl">SUMSS Postage Stamp Server</a>. <p> The SUMSS is intended to complement the NRAO-VLA Sky Survey (NVSS) which covered the sky between +90 and -40 deg declination, at a frequency of 1400MHz. <p> Provenance: The SUMSS project team, University of Sydney. This is a service of NASA HEASARC.
- ID:
- ivo://nasa.heasarc/tartarus
- Title:
- Tartarus: Reduced ASCA AGN Data (Version 3.1)
- Short Name:
- ASCA/AGN
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Tartarus database contains the results of a detailed but systematic analysis of ASCA observations of active galactic nuclei (AGN). It contains source and background events files, spectra, ancillary response files and response matrices, images, and assorted light curves for a large number of ASCA AGN observations. Spectral fit results are done by automatic XSPEC fitting. This database table allows easy access to reduced AGN data for the whole community, allowing the maximum scientific return from the data. Availability of publishable light curves, images, and spectra (which can also be readily re-fitted) should be particularly valuable to astronomers with little direct experience in the reduction of X-ray data. Version 3.1 has been created by analyzing all ASCA observing sequences with targets designated as AGN, as indicated by a leading "7" in the ASCA observing sequence number. Version 3.1 contains products for all 611 observing sequences designated as AGN observations. This is a significant improvement over Versions 1 and 2. Moreover, the 611 sequences for which products are available are complete in the sense that either the target object was not detected (in which case an upper limit on GIS2 source counts is given) or the intended AGN target was detected and the data were fully analyzed. In order to obtain the most accurate background subtraction and minimize contamination from any nearby sources, version 3.1 makes more use of custom extraction regions than previous versions. It is expected that version 3.1 will be replaced when the final ASCA calibration is completed. This database table has been created by the Tartarus Team, and they, rather than Imperial College London or the HEASARC, are responsible for the contents. It was ingested by the HEASARC in August, 2005. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/skyview/hawaii-hdf-b
- Title:
- The Hawaii Hubble Deep Field North: Band B
- Short Name:
- Hawaii HDF B
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Hawaii-HDF-N is an intensive multi-color imaging survey of 0.2 sq. degrees centered on the HDF-N. Data were collected on the NOAO 4m Mayall telescope, the National Astronomical Observatory of Japan 8.2m Subaru telescope and the University of Hawaii 2.2m telescope. Deep U, B, V, R, I, and z' data were obtained over the whole field and deep HK' data over the Chandra Deep Field North. Details are available in the references. [Adapted from reference website.] <P> Two different images are given in the V band (V0201 and V0401) from observations separated by about a month that had substantial differences in seeing. Provenance: Data downloaded from the reference website. A formatting error in the FITS files was corrected.. This is a service of NASA HEASARC.
- ID:
- ivo://nasa.heasarc/skyview/hi4pi
- Title:
- The HI 4-PI Survey
- Short Name:
- HI4PI
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The HI 4-PI Survey (HI4PI) is a 21-cm all-sky survey of neutral atomic hydrogen. It is constructed from the Effelsberg-Bonn HI Survey (EBHIS), made with the 100-m radio telescope at Effelsberg/Germany, and the Galactic All-Sky Survey (GASS), observed with the Parkes 64-m dish in Australia. HI4PI comprises HI line emission from the Milky Way. This dataset is the atomic neutral hydrogen (HI) column density map derived from HI4PI (|Vlsr| < 600 km/s). Provenance: Argelander-Institut für Astronomie (AIfA), Max-Planck-Institut für Radioastronomie (MPIfR), and CSIRO/Australia; data provided by B. Winkel. This is a service of NASA HEASARC.
- ID:
- ivo://nasa.heasarc/skyview/shassa
- Title:
- The Southern H-Alpha Sky Survey Atlas: Continuum
- Short Name:
- SHASSA
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Southern H-Alpha Sky Survey Atlas is the product of a wide-angle digital imaging survey of the H-alpha emission from the warm ionized interstellar gas of our Galaxy. This atlas covers the southern hemisphere sky (declinations less than +15 degrees). The observations were taken with a robotic camera operating at Cerro Tololo Inter-American Observatory (CTIO) in Chile. The atlas consists of 2168 images covering 542 fields. There are four images available for each field: <b>H-alpha</b>, <b>Continuum</b>, <b>Continuum-Corrected</b> (the difference of the H-alpha and Continuum images), and <b>Smoothed</b> (median filtered to 5 pixel, or 4.0 arcminute, resolution to remove star residuals better). The <a href="https://amundsen.swarthmore.edu/SHASSA">SHASSA website</a> has more details of the data and the status of this and related projects. Images can also be obtained from the <a href="https://amundsen.astro.swarthmore.edu/SHASSA/#Images">Download Images</a> section at the SHASSA site. Provenance: John E. Gaustad (Swarthmore College), Peter R. McCullough (University of Illinois), Wayne Rosing (Las Cumbres Observatory), and Dave Van Buren (Extrasolar Research Corporation). This is a service of NASA HEASARC.
- ID:
- ivo://nasa.heasarc/skyview/2mass
- Title:
- Two Micron All Sky Survey (H-Band)
- Short Name:
- 2MASS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 2MASS data were collected by uniformly scanning the entire sky in three near-infrared bands to detect and characterize point sources brighter than about 1 mJy in each band, with signal-to-noise ratio (SNR) greater than 10, using a pixel size of 2.0". This achieves an 80,000-fold improvement in sensitivity relative to earlier surveys. 2MASS used two new, highly-automated 1.3-m telescopes, one at Mt. Hopkins, AZ, and one at CTIO, Chile. Each telescope is equipped with a three-channel camera, each channel consisting of a 256 by 256 array of HgCdTe detectors, capable of observing the sky simultaneously at J (1.25 microns), H (1.65 microns), and K<sub>s</sub> (2.17 microns). <p>2MASS images and other data products can be obtained at the <a href="https://irsa.ipac.caltech.edu/applications/2MASS/QL/">NASA/IPAC Infrared Science Archive</a> Provenance: The Two Micron All Sky Survey is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, funded by the National Aeronautics and Space Administration and the National Science Foundation.. This is a service of NASA HEASARC.
- ID:
- ivo://nasa.heasarc/skyview/ukidss
- Title:
- UKIRT Infrared Deep Survey J-band
- Short Name:
- UKIDSS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The UKIDSS survey is the next generation infrared survey, a successor to 2MASS. It will ultimately cover 7000 square degrees in the northern sky at both high and low Galactic latitudes and goes about three magnitudes deeper than 2MASS in the coverage area. Most data is taken in the J, H and K bands. A Y band is available in some regions. <p> UKIDSS is comprised of several distinct surveys in different regions of the sky. Of primary interest to <i>SkyView</i> users (since they have the largest sky coverage) are the Large Area Survey, the Galactic Plane Survey, and the Galactic Clusters Survey. There are deep and ultadeep surveys which cover much smaller fractions of the sky. The planned coverage for the UKIDSS surveys may be seen at the <a href="http://wsa.roe.ac.uk/theSurveys.html"> UKIDSS survey page</a>. All UKIDSS data products are published by the Wide-Field Astronomy Unit (WFAU) at the University of Edinburgh through the <a href="http://wsa.roe.ac.uk/">WFCAM Science Archive (WSA)</a> which includes more detailed coverage information for each data release. <p> <i>SkyView</i> currently uses the DR11 data release. Many thanks to the WSA team at WFAU for providing an interface to make all the latest data easily accessed. Note that coverage is not uniform across the different bands so that at a given point there might be H and K band data, but nothing in the J band. Provenance: UKIDSS Project. This is a service of NASA HEASARC.
