- ID:
- ivo://nasa.heasarc/texas
- Title:
- Texas Survey of Radio Sources at 365 MHz
- Short Name:
- Texas
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog is from the Texas Survey of discrete radio sources between -35.5 degrees and +71.5 degrees declination (B1950), which was carried out at a frequency of 365 MHz (82 cm wavelength) with the Texas Interferometer during the period from 1974 to 1983. The Survey lists accurate positions with internal errors of about an arcsecond, flux densities (which for strong point sources have internal errors of about 1% and total errors of about 5%), simple structure models and indications of spectrum and variability for 66841 sources. Results of comparisons with other data show that the Survey is 90% complete at 0.4 Jy and 80% complete at 0.25 Jy, is nearly free from spurious sources, and has a lobeshift incidence which is reasonably described by quality flags associated with each source. The University of Texas Radio Astronomy Observatory (UTRAO) carried out, with the Texas Interferometer, this 365 MHz survey of the sky, which was intended to be complete to a flux density level of 0.25 Jy, to provide positions with an accuracy of about 1 arcsec in both coordinates, to give accurate flux densities and indication of source variability, and to give rough structure models for each source. The observations began in 1974 and were completed in 1983. A preliminary version of one declination strip was published (Douglas et al., Publ. Dept. Astron. Univ. Texas, No. 17, Oct. 1980), and a number of intermediate versions of the survey were privately circulated for various purposes, pending completion of the final analysis and adjustment of the data. This database was created by the HEASARC in February 2001, based on CDS/ADC catalog VIII/42. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/swif1swxrt
- Title:
- The Seven-Year Swift-XRT Point Source Catalog (1SWXRT)
- Short Name:
- SWIF1SWXRT
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the 1SWXRT catalog of point sources detected by X-ray Telescope (XRT) on board of the Swift satellite during the first seven years of operation (Jan 2005 - Dec 2011). Swift is a NASA mission with international participation dedicated to 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 seven-year Swift-XRT point source catalog (1SWXRT) was built using all the observations performed by Swift-XRT in PC observing mode with an exposure longer than 500 s. The total number of observations considered is 35011, for an overall exposure time of ~140 Ms. Different observations with same pointing were not merged, but analyzed separately, thus retaining information about the variability of the catalogued sources. Most of the observations have short exposures. In fact, ~18% have t<sub>exp</sub> < 1 ks and ~77% have t<sub>exp</sub> < 5 ks. Only 7% of the observations have an exposure time > 10 ks, which are mostly (but not exclusively) fields associated with GRBs. 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. For each detection the catalog reports three count rates in the 0.3-3 (Soft), and 2-10 (Hard), and 0.3-10 (Full) keV energy bands. Each are 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 from spurious and extended sources by visual inspection of all the observations. Count rates in the three bands were converted to 0.5-10, 0.5-2, and 2-10 keV observed fluxes, respectively. For the fluxes these energy bands were adopted to easy comparison with other X-ray catalogs (Watson, M. G. et al. 2009, A&A, 493, 339; Evans, I. N. et al. 2010, ApJ, 189, 37). The count rate to flux conversion was made using an absorbed power-law. The absorption is the Galactic hydrogen column density in the direction of the source and the photon spectral index has been estimated through the hardness ratio. Each row in the catalog is a detection not a unique source since the analysis was done by observation. Since multiple observations have covered the same part of the sky, a source may be detected more than once. The total number of detections is 84979 with an estimated 36000 unique sources as reported in the D'Elia et al. paper. The number of unique sources is derived by considering as one source all detections that have their positions within 12 arcsec. However, the catalog does not have a marker to identify all detections of a unique source. 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/1swxrt/">https://www.asdc.asi.it/1swxrt/</a> and published in the Astronomy and Astrophysics Journal. This catalog is also available as <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/551/A142">CDS catalog J/A+A/551/A142</a>. The HEASARC added the id_number parameter, a counter to numerically identify each detection in the catalog (since the names of the detections are not unique), . Note that there is a discrepancy in the number of detections in the electronic version which has 84979 records and the number of detections reported in the paper (84992). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/wrcat
- Title:
- The VIIth Catalog of Galactic Wolf-Rayet Stars
- Short Name:
- WR
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The VIIth Catalogue of Galactic Population I Wolf-Rayet (WR) Stars provides improved coordinates, spectral types, and bv photometry of known WR stars and adds 71 new stars compared to the VIth Catalog. This census of galactic WR stars has reached 227 stars (226 entries in this catalog), comprising 127 WN stars, 87 WC stars, 10 WN/WC stars, and 3 WO stars. This includes 15 WNL and 11 WCL stars within 30 pc of the Galactic Center. The catalog includes information on periodicity, binarity, terminal wind velocities, correlations with open clusters, OB associations, H I bubbles, H II regions, and ring nebulae, observed and dereddened narrow-band bv photometry, and distances, both heliocentric and galactocentric, and lists the references from which this information was obtained. This catalog was created by the HEASARC in April 2001, based on electronic versions of Tables 13, 14, 15, and 28 from the published paper containing the catalog which were directly supplied to the HEASARC by the author. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/fermi3fhl
- Title:
- Third Catalog of Hard Fermi-LAT Sources (3FHL)
- Short Name:
- FERMI3FHL
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This is a catalog of sources detected above 10 GeV by the Fermi-Large Area Telescope (LAT) in the first 7 years of data using the Pass 8 event-level analysis. It contains 1558 objects characterized in the 10 GeV to 2 TeV energy range. The sensitivity and angular resolution are improved by factors of 3 and 2 relative to the previous LAT catalog at the same energies (1FHL). The vast majority of detected sources (79%) are extragalactic, including 16 sources located at very high redshift (z > 2). Nine percent of the sources are Galactic and 12% are unassociated (or associated with a source of unknown nature). The high-latitude sky and the Galactic plane are observed with an average sensitivity of 0.5% and 1% of the Crab Nebula flux above 10 GeV, respectively. The catalog includes 225 new gamma-ray sources. The substantial increase in the number of photons (more than 4 times relative to the 1FHL and 10 times to the 2FHL) also allows us to characterize spectral curvature for 32 sources and flux variability for 163 of them. Furthermore, we estimate that for the same energy flux limit of 10<sup>-12</sup> erg cm<sup>2</sup> s<sup>-1</sup>, the energy range above 10 GeV has twice as many sources as the range above 50 GeV, which confirms and quantifies the importance of lowering the energy threshold of Cherenkov telescopes as much as possible in order to increase the number of available sources. This database table was first ingested by the HEASARC in December 2017 using electronic data obtained from the Fermi Science Support Center (FSSC). That data is available at <a href="http://fermi.gsfc.nasa.gov/ssc/data/access/lat/3FHL/">http://fermi.gsfc.nasa.gov/ssc/data/access/lat/3FHL/</a>. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rc3
- Title:
- Third Reference Catalog of Bright Galaxies
- Short Name:
- RC3
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the machine-readable version of the Third Reference Catalogue of Bright Galaxies (RC3) by G. de Vaucouleurs, A. de Vacouleurs, H.G. Corwin, R.J. Buta, P. Fouque, and G. Paturel, originally published by Springer-Verlag in 1991, and including some corrections and additions made by Corwin et al. (1994, AJ, 108, 2128). Only brief parameter descriptions are given in this help file. Detailed information about, for example, how certain quantities were derived, or exactly what a given code means, can be found in the printed version of RC3. This table was created by the HEASARC in March 2007 based on CDS table VII/155/rc3, and replaced an earlier version which did not contain the corrections made by Corwin et al. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/trifidcxo
- Title:
- Trifid Nebula (M 20) Chandra X-Ray Point Source Catalog
- Short Name:
- TRIFIDCXO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a list of the Trifid Nebula (M 20) X-Ray point sources detected by the Chandra X-ray Observatory (CXO) in an observation carried out on 2002 June 13. The Trifid Nebula, a young star-forming H II region, was observed for 16 hr by the Advanced CCD Imaging Spectrometer imaging array, ACIS-I, detector. 304 X-ray sources were detected, 30% of which are hard sources (defined as those sources having a 0.5-2.0 keV to 2.0-8.0 keV hardness ratio > -0.2) and 70% of which have near-infrared counterparts. This table was created by the HEASARC in January 2007 based on CDS table J/ApJ/607/904/table1.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gc47tuccx2
- Title:
- 47 Tuc Globular Cluster Chandra X-Ray Point Source Catalog (2017 Version)
- Short Name:
- GC47TUCCX2
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors combined Chandra ACIS observations of the globular cluster 47 Tucanae (47 Tuc) from 2000, 2002, and 2014-2015 to create a deeper X-ray source list and study some of the faint radio millisecond pulsars (MSPs) present in this cluster. This work combined 180 ks of new Chandra ACIS data on 47 Tuc with 370 ks of archival data and used improved algorithms to generate a new source catalog, finding 81 new sources for a total of 370 within the half-mass region (2.79 arcsec) of the cluster. The majority of the newly identified sources are in the crowded core region, indicating cluster membership. The authors associated five of the new X-ray sources with chromospherically active BY Dra or W UMa variables identified by Albrow et al. (2001, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/559/1060">CDS Cat. <J/ApJ/559/1060></a>). See also the related <a href="gc47tuccxo.html">2005 source catalog</a>. This table was created by the HEASARC in September 2020 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/472/3706">CDS Catalog J/MNRAS/472/3706</a> files table2.dat, table4.dat, and table5.dat. The optical names from Albrow et al. (2001) were subsequently corrected in October 2020 in order to use the recommendation from the CDS Dictionary of Nomenclature of Celestial Objects. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gc47tuccxo
- Title:
- 47 Tuc Globular Cluster Chandra X-Ray Point Source Catalog (2005 Version)
- Short Name:
- GC47TUCCXO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have detected 300 X-ray sources within the half-mass radius (2.79') of the globular cluster 47 Tucanae in a deep (281 ks) Chandra exposure. They perform photometry and simple spectral fitting for our detected sources and construct luminosity functions, X-ray color-magnitude, and color-color diagrams. Eighty-seven X-ray sources show variability on timescales from hours to years. Thirty-one of the new X-ray sources are identified with chromospherically active binaries from the catalogs of Albrow and coworkers (2001, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/559/1060">CDS Catalog <J/ApJ/559/1060></a>). The authors estimate that the total number of neutron stars in 47 Tuc is of order 300, reducing the discrepancy between theoretical neutron star retention rates and observed neutron star populations in globular clusters. The data used in this paper are from the 2000 and 2002 Chandra observations of the globular cluster 47 Tuc. The 2000 observations, initially described in Grindlay et al. (2001, Science 292, 2290), were performed with the ACIS-I CCD array at the telescope focus, while the 2002 observations placed the back-illuminated ACIS-S aim point at the focus for maximum low-energy sensitivity. The authors combined the results from wavdetect source detection runs with a threshold probability of 1 x 10<sup>-5</sup>, in two energy bands (0.5 - 2.0 keV and 0.5 - 6.0 keV for the 2000 observations, and (0.3 - 2.0 keV and 0.3 - 6.0 keV for the 2002 observations), to make independent source lists for the 2000 and 2002 observations, given in Tables 2 and 3 of the reference paper, which have been combined in the present HEASARC table. A total of 146 sources were detected in this way in the 2000 observations (entries with dataset_year = 2000), while 300 sources were detected in the 2002 observations (dataset_year = 2002). A total of 143 of the sources were clearly detected in both observations, while only three of the sources from the 2000 observations were not detected in the 2002 observations. See also the related <a href="gc47tuccx2.html">2017 source catalog</a>. This table was created by the HEASARC in June 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/625/796">CDS Catalog J/ApJ/625/796</a> files table2.dat, table3.dat, and (part of) table5.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/tramisuboo
- Title:
- Two-Meter Radio Mini Survey (T-RaMiSu) of the Bootes Field
- Short Name:
- TRAMISUBOO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains results from wide-area, deep, high-resolution 153-MHz GMRT observations of the NOAO Bootes field, adding to the extensive, multi-wavelength data of this region. The observations, data reduction, and catalog construction and description are described in the reference paper. The seven pointings (listed in Table 2 of the reference paper) produced a final mosaic covering 30 square degrees with a resolution of 25". The rms noise is 2 mJy/beam in the center of the image, rising to 4-5 mJy/beam at the edges, with an average of 3 mJy/beam. Seventy-five per cent of the area has an rms < 4 mJy/beam. The extracted source catalog contains 1289 sources detected at 5 sigma at flux densities between 4.1 mJy and 7.3 Jy, of which 453 are resolved. The authors estimate the catalogue to be 92% reliable and 95% complete at an integrated flux density limit of 14 mJy. The flux densities and astrometry have been corrected for systematic errors. In their paper, the authors calculate the differential source counts which are in good agreement with those in the literature and provide an important step forward in quantifying the source counts at these low frequencies and low flux densities. The GMRT 153-MHz sources have been matched to the 1.4-GHz NVSS and 327-MHz WENSS catalogs and spectral indices were derived. The source catalog presented here is derived from seven 4 hour pointings with the GMRT at 153 MHz, centered on the NOAO Bootes field. The resulting 30 square degree image has a central noise level of 2 mJy/beam and a resolution of 25". This table contains entries for all 1289 detected 153-MHz radio sources as well as for the 160 Gaussian components of the 77 sources (71 doubles and 3 triples) which could be fit by multiple Gaussian components, making a total of 1449 entries. This table was created by the HEASARC in January 2013 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/549/A55">CDS Catalog J/A+A/549/A55</a> files table2.dat and table3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/tycho2
- Title:
- Tycho-2 Catalog of the 2.5 Million Brightest Stars
- Short Name:
- Tycho-2
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Hipparcos and Tycho catalogs are the primary products of the European Space Agency's astrometric mission, Hipparcos. The satellite, which operated for four years, returned high quality scientific data from November 1989 to March 1993. The Tycho-2 catalog is an astrometric reference catalog containing positions and proper motions as well as two-color photometric data for the 2.5 million brightest stars in the sky. The Tycho-2 positions and magnitudes are based on precisely the same observations as the original Tycho catalog (hereafter Tycho-1; see <a href="https://cdsarc.cds.unistra.fr/ftp/cats/I/239">CDS Cat. I/239</a>) collected by the star mapper of the ESA Hipparcos satellite, but Tycho-2 is much bigger and slightly more precise, owing to a more advanced reduction technique. Components of double stars with separations down to 0.8 arcsec are included. Proper motions precise to about 2.5 mas/yr are given as derived from a comparison with the Astrographic Catalogue and 143 other ground-based astrometric catalogs, all reduced to the Hipparcos celestial coordinate system. Tycho-2 supersedes in most applications Tycho-1, as well as the ACT (<a href="https://cdsarc.cds.unistra.fr/ftp/cats/I/246">CDS Cat. I/246</a>) and the TRC (CDS Cat. I/250) catalogs based on Tycho-1. Supplement-1 (not part of this HEASARC database but available at <a href="https://cdsarc.cds.unistra.fr/ftp/cats/I/259/suppl_1.dat.gz">https://cdsarc.cds.unistra.fr/ftp/cats/I/259/suppl_1.dat.gz</a>) lists stars from the Hipparcos and Tycho-1 catalogs which are not in Tycho-2. Supplement-2 (not part of this HEASARC database but available at <a href="https://cdsarc.cds.unistra.fr/ftp/cats/I/259/suppl_2.dat.gz">https://cdsarc.cds.unistra.fr/ftp/cats/I/259/suppl_2.dat.gz</a>) lists 1146 Tycho-1 stars which are probably either false or heavily disturbed. The principal characteristics of the Tycho-2 catalog are summarized below. By means of proper motions the positions are transferred to the year 2000.0, the epoch of the catalog. The median values of internal standard errors are given: <pre> Mean satellite observation epoch ~J1991.5 Epoch of the Tycho-2 catalog J2000.0 Reference system ICRS coincidence with ICRS (1) +/-0.6 mas deviation from inertial (1) +/-0.25 mas/yr Number of entries 2,539,913 Astrometric standard errors (2) V_T < 9 mag 7 mas all stars, positions 60 mas all stars, proper motions 2.5 mas/yr Photometric std. errors (3) on V_T V_T < 9 mag 0.013 mag all stars 0.10 mag Star density b= 0 deg 150 stars/sq.deg. b= +/-30 deg 50 stars/sq.deg. b= +/-90 deg 25 stars/sq.deg. Completeness to 90 per cent V ~ 11.5 mag Completeness to 99 per cent V ~ 11.0 mag Number of Tycho observations ~300 10<sup>6</sup> Note (1): about all 3 axes Note (2): ratio of external to internal standard errors is ~1.0 for positions and for proper motions. Systematic errors are less than 1 mas and 0.5 mas/yr Note (3): ratio of photometric external to internal standard errors at V_T > 9 mag is below 1.5 </pre> For more information on the original catalog, please consult the Tycho-2 home page at <a href="http://www.astro.ku.dk/~erik/Tycho-2">http://www.astro.ku.dk/~erik/Tycho-2</a> For more information on the HEASARC implementation of the Tycho-2 catalog, please consult <a href="#heasarc_implementation">the "HEASARC Implementation" section</a> of this help. This database table was created at the HEASARC in June 2000 based on the ADC/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/I/259">CDS Catalog I/259</a>, using the file tyc2.dat. Galactic coordinates (calculated by converting the observed ICRS Equatorial positions) were added to this HEASARC database table in August 2005. This is a service provided by NASA HEASARC .
