- ID:
- ivo://nasa.heasarc/galexlog
- Title:
- Galaxy Evolution Explorer (GALEX) Observation Log
- Short Name:
- GALEXLOG
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the Galaxy Evolution Explorer (GALEX) observation log of the extant and planned observations to be made by this satellite observatory. The Galaxy Evolution Explorer (GALEX) is a NASA Small Explorer Mission launched on April 28, 2003. GALEX has been performing the first Space Ultraviolet sky survey. Five imaging surveys in each of two bands (FUV: 1350-1750 Angstroms and NUV: 1750-2800 Angstroms) range from an all-sky survey (limiting m<sub>AB</sub> ~ 20 - 21) to an ultra-deep survey of 4 square degrees (limiting m<sub>AB</sub> ~ 26). Three spectroscopic grism surveys (spectral resolution R = 100 - 300) are underway with various depths (m<sub>AB</sub> ~ 20 - 25) and sky coverage (100 to 2 square degrees) over the 1350 - 2800 Angstroms spectral range. The instrument includes a 50-cm modified Ritchey-Chretien telescope, a dichroic beam splitter and astigmatism corrector, two large, sealed-tube microchannel plate detectors to simultaneously cover the two bands and the 1.2-degree field of view. A rotating wheel provides either imaging or grism spectroscopy with transmitting optics. The GALEX mission also includes an Associate Investigator program for additional observations and supporting data analysis which supports a wide variety of investigations made possible by the first UV sky survey. The HEASARC provides this table of GALEX observations as an assistance to the high-energy astrophysics community, e.g., to enable cross-correlations of GALEX with X-ray observations. The GALEX data are available via MAST at <a href="http://galex.stsci.edu/">http://galex.stsci.edu/</a>. More information about GALEX can be found at <a href="http://www.galex.caltech.edu/">http://www.galex.caltech.edu/</a> and <a href="https://asd.gsfc.nasa.gov/archive/galex/">https://asd.gsfc.nasa.gov/archive/galex/</a>. This table was first created in July 2010 using the input file <a href="http://sherpa.caltech.edu/gips/ref/galex_obs_status.csv">http://sherpa.caltech.edu/gips/ref/galex_obs_status.csv</a> obtained from the Caltech GALEX site. This table is updated within a week of the update of the original file. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/skyview/galex
- Title:
- Galaxy Explorer All Sky Survey: Near UV
- Short Name:
- GALEX
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The GALEX, Galaxy Explorer, mission was launched by a Pegasus-XL vehicle on April 28 2003 into a 690km altitude, 29 degree inclination, circular orbit with a 98.6 minute period. The GALEX instrument allows imaging and spectroscopic observations to be made in two ultraviolet bands, Far UV (FUV) 1350-1780A and Near UV (NUV) 1770-2730A. The instrument provides simultaneous co-aligned FUV and NUV images with spatial resolution 4.3 and 5.3 arcseconds respectively. Details of the performance of the instrument and detectors can be found in Morrissey et al. (2007) ApJS, 173, 682. <p> The <i>SkyView</i> GALEX surveys mosaic the intensity images of All-Sky Survey images. For a given pixel only the nearest image is used. Since a given GALEX observation is circular, this maximizes the coverage compared with default image finding algorithms which use the distance from edge of the image. <p> As of February 10, 2011, SkyView uses the GALEX GR6 data release. Provenance: All data is downloaded from the <a href="https://galex.stsci.edu"> MAST GALEX archive</a>.. This is a service of NASA HEASARC.
- ID:
- ivo://nasa.heasarc/glxsdssqso
- Title:
- GALEX/SDSS Quasar Catalog
- Short Name:
- GLXSDSSQSO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the result of an analysis of the broad-band UV and optical properties of z ~< 3.4 quasars matched in the Galaxy Evolution Explorer (GALEX) General Data Release 1 (GR1) and the Sloan Digital Sky Survey (SDSS) Data Release 3 (DR3). Of the 6371 SDSS DR3 quasars covered by 204 GALEX GR1 tiles and listed in this table, 5380 (84%) have near-UV detections, while 3034 (48%) have both near-UV and far-UV detections using a matching radius of 7 arcseconds. Most of the DR3 sample quasars are detected in the near-UV until z ~ 1.7, with the near-UV detection fraction dropping to ~50% by z ~ 2. Statistical tests performed on the distributions of non-detections indicate that the optically selected quasars missed in the UV tend to be optically faint or at high redshift. The GALEX positions are shown to be consistent with the SDSS astrometry to within an rms scatter of 0.6 - 0.7 arcsecs in each coordinate, and the empirically determined photometric errors from multi-epoch GALEX observations significantly exceed the Poissonian errors quoted in the GR1 object catalogs. The UV-detected quasars are well separated from stars in UV-optical color-color space, with the UV-optical relative colors suggesting a marginally detected population of reddened objects due to absorption along the line of sight or dust associated with the quasar. The resulting spectral energy distributions (SEDs) cover ~350 - 9000 Angstroms (rest frame), where the overall median SED peaks near the Lyman-Alpha emission line, as found in other UV quasar studies. The large sample size allows the authors to construct median SEDs in small bins of redshift and luminosity, and they find that the median SED becomes harder (bluer) at UV wavelengths for quasars with lower continuum luminosity. The detected UV-optical flux as a function of redshift is qualitatively consistent with attenuation by intervening Lyman-absorbing clouds. This table was created by the HEASARC in October 2009 based on the electronic version of Table 2 from the reference paper which was obtained from the CDS (their catalog J/AJ/133/1780 file table2.dat). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/glxsdssqs2
- Title:
- GALEX/SDSS z=0.5-1.5 QSO Candidates Catalog
- Short Name:
- GLXSDSSQS2
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- A sample of ~60,000 objects from the combined Sloan Digital Sky Survey-Galaxy Evolution Explorer (SDSS-GALEX) database with UV-optical colors that should isolate QSOs in the redshift range 0.5 to 1.5 is discussed. The authors use SDSS spectra of a subsample of ~ 4,500 to remove stellar and galaxy contaminants in the sample to a very high level, based on the 7-band photometry. In their paper, they discuss the distributions of redshift, luminosity, and reddening of the 19,100 QSOs (~96%) that they estimate to be present in their final sample of 19,812 point sources. This latter catalog is available in the present table. This paper is based on archival data from the Galaxy Evolution Explorer (GALEX) which is operated for NASA by the California Institute of Technology under NASA contract NAS5-98034, and on data from the SDSS. This table was created by the HEASARC in March 2011 based on the electronic version of Table 2 from the reference paper which was obtained from the AJ web site. Some of the values for the name parameter in the HEASARC's implementation of this table were corrected in April 2018. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/galextdsc
- Title:
- GALEX Time Domain Survey Catalog
- Short Name:
- GALEXTDSC
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains results from the selection and classification of over a thousand ultraviolet (UV) variable sources discovered in ~ 40 deg<sup>2</sup> of GALEX Time Domain Survey (TDS) NUV images observed with a cadence of 2 days and a baseline of observations of ~ 3 years. The GALEX TDS fields were designed to be in spatial and temporal coordination with the Pan-STARRS1 Medium Deep Survey, which provides deep optical imaging and simultaneous optical transient detections via image differencing. The authors characterize the GALEX photometric errors empirically as a function of mean magnitude, and select sources that vary at the 5-sigma level in at least one epoch. They measure the statistical properties of the UV variability, including the structure function on timescales of days and years, and report classifications for the GALEX TDS sample using a combination of optical host colors and morphology, UV light curve characteristics, and matches to archival X-ray, and spectroscopy catalogs. The authors classify 62% of the sources as active galaxies (358 quasars and 305 active galactic nuclei), and 10% as variable stars (including 37 RR Lyrae, 53 M dwarf flare stars, and 2 cataclysmic variables). They detect a large-amplitude tail in the UV variability distribution for M-dwarf flare stars and RR Lyrae, reaching up to |Delta-M| = 4.6 and 2.9 magnitudes, respectively. The mean amplitude of the structure function for quasars on year timescales is five times larger than observed at optical wavelengths. The remaining unclassified sources include UV-bright extragalactic transients, two of which have been spectroscopically confirmed to be a young core-collapse supernova and a flare from the tidal disruption of a star by a dormant super-massive black hole. The authors calculate a surface density for variable sources in the UV with NUV < 23 mag and |Delta-M| > 0.2 mag of ~ 8.0, 7.7, and 1.8 deg<sup>-2</sup> for quasars, AGN, and RR Lyrae stars, respectively, and a surface density rate in the UV for transient sources, using the effective survey time at the cadence appropriate to each class, of ~15 and 52 deg<sup>-2</sup> yr<sup>-1</sup> for M dwarfs and extragalactic transients, respectively. The GALEX observations were made using the NUV detector which has an 1.25 degree diameter field of view and an effective wavelength of 2316 Angstroms. During the window of observing visibility of each GALEX TDS field (from two to four weeks, one to two times per year), they were observed with a cadence of 2 days, and a typical exposure time per epoch of 1.5 ks (or a 5-sigma point-source limit of m<sub>AB</sub>(NUV) ~ 23.3 magnitude), with a range from 1.0 to 1.7 ks. Table 2 in the reference paper lists the RA and Dec of their centers, the Galactic extinction E(B - V ) for each field from the Schlegel et al. (1998, ApJ, 500, 525) dust maps, and the number of epochs per field. This table was created by the HEASARC in May 2013 based on a machine-readable version of Table 4 from the paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/ipngrb
- Title:
- Gamma-Ray Bursts from the Interplanetary Network
- Short Name:
- GRB/IPN
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Interplanetary Network (IPN) is a group of spacecraft equipped with gamma-ray burst detectors used to localize gamma-ray bursts (GRB) and soft gamma repeaters (SGRs, or magnetars). The astronomical locations of GRBs are determined by the comparison of the arrival times of the event at the locations of the detectors used on different space missions. The precision is proportional to the distance of spacecraft separations, so that the localizational accuracy of a network with baselines of thousands of light-seconds can be equal or superior to that of any other technique. The primary disadvantage of the IPN method, however, is the 1-day to 1.5-day delay in the acquisition of data from all the spacecraft in the network. Interplanetary GRB networks have been in existence since 1977, contributing to the studies of various astrophysical gamma-ray transients, most notably GRBs and SGRs (soft gamma repeaters). The IPN3 began operations in 1990, with the launch of the Ulysses spacecraft. It was joined by the Compton Gamma Ray Observatory in 1991. Pioneer Venus Orbiter, Mars Observer, and the Italian X-ray astronomy satellite BeppoSAX were part of the network while they were operating. Twenty-six experiments or missions have joined the network so far. Today, the main spacecrafts contributing their data are Konus-WIND, Mars Odyssey, INTEGRAL, RHESSI, Swift, Agile, BepiColombo, and Fermi. XMM-Newton and MAXI are kept to record the cosmic ray and SGR but not used for triangulation because of the different energy range. The IPNGRB database table is derived from a list provided by Kevin Hurley <khurley@ssl.berkeley.edu>, based on the IPN3. The initial list also includes particles and solar events as well as unconfirmed SGRs and GRBs. The IPNGRB database includes only the observations of confirmed cosmic gamma-ray bursts and SGR since the launch of the Ulysses spacecraft. It is updated every time a new list is provided to the HEASARC. This HEASARC catalog is derived from the master list of IPN3 events provided by Kevin Hurley. He also provided a FORTRAN program that generates the list of selected events. The output of this program is run at GSFC and ingested into the HEASARC database system. Information on the IPN3 system is available at <a href="http://ipn3.ssl.berkeley.edu/">http://ipn3.ssl.berkeley.edu/</a>. <p> Information on the IPN can be found at <a href="http://heasarc.gsfc.nasa.gov/docs/heasarc/missions/ipn.html">http://heasarc.gsfc.nasa.gov/docs/heasarc/missions/ipn.html</a>. <p> In December 2021 Kevin Hurley passed away. He was one of the initiator of the IPN and its evolution. The last table provided is dated August 2021. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/mggammadet
- Title:
- Gamma-RaySourceDetailedCatalog(Macomb&Gehrels1999)
- Short Name:
- MGGAMMADET
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table contains the slightly revised contents of the detailed Tables 2A - 2G from the General Gamma-Ray Source Catalog of Macomb & Gehrels (1999). It lists details of all known gamma-ray observations within the energy range from 50 keV to ~1 TeV for 314 discrete gamma-ray sources that were listed in Tables 2A - 2G of the published version of this catalog, including all 310 sources listed in the published Summary Table 1, together with 4 sources (2CG 054+01, A0620-00, GX 340+0, and H1822-000) that were listed only in Table 2 of the published catalog but were (presumably accidentally) omitted from Table 1. The positions for the sources in the present database were taken from Table 1 of the General Gamma-Ray Source Catalog. Thus, this table is essentially a compilation of gamma-ray observations of discrete sources as known to the authors as of early 1999. There is another HEASARC database table called the Gamma-Ray Source Summary Catalog (Macomb & Gehrels 1999) or MGGAMMACAT that contains the summary information on these sources that was given in Table 1 of the General Gamma-Ray Source Catalog. As noted above, this is a slightly revised version compared to the published Tables 2A - 2G. The known differences between the HEASARC and published versions are discussed in the HEASARC_Version section of the help documentation. This database table was created by the HEASARC in March 2002 based upon machine-readable versions of Tables 2A-2G of the Macomb & Gehrels (1999) General Gamma-Ray Source Catalog that were supplied by the authors. One duplicate entry was removed from this table in June 2019. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/mggammacat
- Title:
- Gamma-RaySourceSummaryCatalog(Macomb&Gehrels1999&2001)
- Short Name:
- M&GGamma-ray
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table is a revised and updated version of the published General Gamma-Ray Source Catalog (Macomb & Gehrels 1999, ApJS, 120, 335). It contains all 309 gamma-ray point sources listed in Table 1 of the published version of this catalog; 4 gamma-ray point sources (2CG 054+01, A0620-00, GX 340+0, and H1822-000) added by the HEASARC that were listed in Table 2 of the published catalog but were (presumably accidentally) omitted from Table 1 of the published catalog; and 107 sources (106 sources from the 3rd Egret (3EG) catalog of Hartman et al. (1999, ApJS, 123, 79) and GEV J1732-3130) that were compiled by Macomb and Gehrels subsequent to their original publication (Macomb and Gehrels 2001, unpublished). Thus, the present database table is essentially a summary master list of all detected gamma-ray point sources as of circa 2000. There is another HEASARC database table called the Gamma-Ray Source Detailed Catalog (Macomb & Gehrels 1999 & 2001) or MGGAMMADET that contains detailed information on the gamma-ray properties of these sources such as fluxes and spectral indices and that is based on Tables 2A-2G of the Macomb & Gehrels paper. This database table was created by the HEASARC in March 2001 based on tables supplied to the HEASARC by the catalog authors which contained an updated version of Table 1 from the published paper. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gcvsegvars
- Title:
- General Catalog of Variable Stars (GCVS4.2): Extragalactic Variables
- Short Name:
- GCVS/X-gal
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The General Catalog of Variable Stars (GCVS) is the only reference source on all known variable stars. This database is based on the electronically-readable version as distributed by the Sternberg Astronomical Institute and Institute of Astronomy (Russian Acad. Sci.), Moscow. It is the catalog of extragalactic variable stars, an updated version of the list contained in the GCVS (4th edition), Volume V. The total number of entries in this database is 10979 variable stars in 35 stellar systems (including the Magellanic Clouds, the Andromeda Galaxy, etc.). These variables include 144 stars now considered to be non-members of the galaxies in whose fields they lie, and 92 more stars that are possible non-members. The present improved electronic version of the GCVS 4th Edition, Volumes I-V, combined with the Name-Lists of Variable Stars Nos. 67 - 77, is also available from the Sternberg Institute via anonymous ftp to <a href="ftp://ftp.sai.msu.su/pub/groups/cluster/gcvs/gcvs/">ftp://ftp.sai.msu.su/pub/groups/cluster/gcvs/gcvs/</a> and more information is available via the Web at <a href="http://www.sai.msu.su/groups/cluster/gcvs/gcvs/">http://www.sai.msu.su/groups/cluster/gcvs/gcvs/</a>. This online version of the GCVS Vol. V Catalog of Extragalactic Variable Stars was created by the HEASARC in January 2005 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/II/250">CDS Catalog II/250</a>, table evs_cat.dat. The latter was itself based on on an electronically-readable version that was distributed by the Sternberg Astronomical Institute and Institute of Astronomy (Russian Acad. Sci.), Moscow. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gcvs
- Title:
- General Catalog of Variable Stars (June 2022 Version)
- Short Name:
- GCVS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Work aimed at compiling detailed catalogs of variable stars in the Galaxy, which has been carried out continuously by Moscow variable-star researchers since 1946 on behalf of the International Astronomical Union, has entered the stage of the publication of the 5th, completely electronic edition of the General Catalog of Variable Stars (GCVS). The GCVS 5.1 is freely accessible on the Internet. The authors recommend citing their paper as a unified reference to the 5th edition of the GCVS. The GCVS is the only reference source on all known variable stars. This version contains the electronically-readable version as distributed by the Sternberg Astronomical Institute and Institute of Astronomy (Russian Acad. Sci.), Moscow. After the publication of Volume III of the 4th edition of the GCVS, the subsequent Name-lists with numbers from 67 to 77 contained only names of variable stars in the GCVS systems, together with their coordinates and variability types. The authors actually started compiling the 5th edition of the GCVS ten years ago, with the 78th Name-list of Variable Stars, which provided (as did all subsequent Name-lists) complete GCVS information for each star (in addition to the variability types, ranges of brightness variations, epochs of brightness maxima or minima, periods, etc.). In all, the 78th-81st Name-lists contain more than 13300 variable stars. The complete revision of information on the coordinates of variable stars (see the Introduction section of the reference paper) was also a part of the transition to the 5th edition. The present electronic version of the GCVS5.1 is available from Sternberg Astronomical Institute (Lomonosov Moscow University) and Institute of Astronomy (Russian Academy of Sciences) at <a href="http://www.sai.msu.su/gcvs/gcvs/">http://www.sai.msu.su/gcvs/gcvs/</a> as a first release of the fifth GCVS edition. Information on the contents and principles of the fifth edition can be found in Samus et al. (2017), the official reference to GCVS 5.1. The GCVS 5.1 version contains data for individual variable objects discovered and named as variable stars by 2021 and located mainly in the Milky Way galaxy. The total number of named variable stars, not counting designated non-existing stars or stars subsequently identified with earlier-named variables, is now 58035. The stars of the GCVS 5.1 are stars of the GCVS fourth edition plus Name-lists Nos. 67-84. The stars from the Name-lists Nos.78-84 are presented in the complete GCVS format. Complete information for stars of the Name-lists Nos. 67-77 is so far provided in the first 20 constellations (Andromeda to Cepheus). In these constellations, the GCVS information has been completely revised with active use of new publications as well as observations retrieved by the GCVS compilers by data mining and used to determine new variability types and new light elements whenever possible. The authors are continuing this work and will introduce new data for the next constellations as soon as they are ready. This version of the GCVS catalog was last updated by the HEASARC in September 2022, based on the file at <a href="http://www.sai.msu.su/gcvs/gcvs/gcvs5/gcvs5.txt">http://www.sai.msu.su/gcvs/gcvs/gcvs5/gcvs5.txt</a>. This is a service provided by NASA HEASARC .
