- ID:
- ivo://nasa.heasarc/wibrals
- Title:
- WISE Blazar-like Radio-Loud Source (WIBRaLS) Catalog
- Short Name:
- WIBRALS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of radio-loud candidate gamma-ray emitting blazars with WISE mid-infrared colors similar to the colors of confirmed gamma-ray blazars. The catalog is assembled from WISE sources detected in all four WISE filters, with colors that are compatible with the three-dimensional locus of the WISE gamma-ray emitting blazars, and which can be spatially cross-matched with radio sources from one of the three radio surveys: NVSS, FIRST, and/or SUMSS. The authors' initial WISE selection uses a slightly modified version of previously successful algorithms. They then select only the radio-loud sources using a measure of the radio-to-IR flux, the q<sub>22</sub> parameter, which is analogous to the q<sub>24</sub> parameter known in the literature but which instead uses the WISE band-four flux at 22 micron (µm). Their final catalog contains 7,855 sources classified as BL Lacs, FSRQs, or mixed candidate blazars; 1,295 of these sources can be spatially re-associated as confirmed blazars. In their paper, the authors describe the properties of the final catalog of WISE blazar-like radio-loud sources and consider possible contaminants. Finally, they discuss why this large catalog of candidate gamma-ray emitting blazars represents a new and useful resource to address the problem of finding low-energy counterparts to currently unidentified high-energy sources. The WISE magnitudes in the [3.4], [4.6], [12] and [22] um nominal filters are in the Vega system. The values of three WISE magnitudes, namely [3.4], [4.6], and [12], and of the colors derived using those magnitudes, have been corrected for galactic extinction according to the extinction law presented by Draine (2003, ARA&A, 41, 241). In their study, the authors adopt the nomenclature proposed in the Multi-wavelength Blazar Catalog (BZCat) that labels BL Lac objects as 'BZBs' and flat-spectrum radio quasars (FSRQs) as 'BZQs'. This table was created by the HEASARC in December 2014 based on a machine-readable version of Table 4 from the reference paper that was obtained from the ApJS web site. This is a service provided by NASA HEASARC .
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Search Results
- ID:
- ivo://nasa.heasarc/w2ragncat
- Title:
- WISE/2MASS/RASS (W2R) AGN Sample Catalog
- Short Name:
- W2RAGNCAT
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors of this catalog have developed the S<sub>IX</sub> statistic to identify bright, highly likely active galactic nucleus (AGN) candidates solely on the basis of Wide-field Infrared Survey Explorer (WISE), Two-Micron All-Sky Survey (2MASS), and ROSAT All-Sky Survey (RASS) data. This statistic was optimized with data from the preliminary WISE survey and the Sloan Digital Sky Survey, and tested with Lick 3 m Kast spectroscopy. The authors find that sources with S<sub>IX</sub> < 0 have a >~ 95% likelihood of being an AGN (defined in this paper as a Seyfert 1, quasar, or blazar). This statistic was then applied to the full WISE/2MASS/RASS dataset, including the final WISE data release, to yield the "W2R" sample of 4316 sources with S<sub>IX</sub> < 0. Only 2209 of these sources are currently in the Veron-Cetty and Veron (VCV) Catalog of spectroscopically confirmed AGNs, indicating that the W2R sample contains nearly 2000 new, relatively bright (J <~ 16) AGNs. The authors utilize the W2R sample to quantify biases and incompleteness in the VCV Catalog. They find that it is highly complete for bright (J < 14), northern AGNs, but the completeness drops below 50% for fainter, southern samples and for sources near the Galactic plane. This approach also led to the spectroscopic identification of 10 new AGNs in the Kepler field, more than doubling the number of AGNs being monitored by Kepler. The W2R sample contains better than 1 bright AGN every 10 deg<sup>2</sup>, permitting construction of AGN samples in any sufficiently large region of sky. This table contains the 4316 sources comprising the W2R sample. This table was created by the HEASARC in June 2012 based on an electronic version of Table 3 from the reference paper which was obtained from the ApJ website. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/wmapcmbfps
- Title:
- WMAP Nine-Year CMB-Free QVW Point Source Catalog
- Short Name:
- WMAPCMBFPS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Wilkinson Microwave Anisotropy Probe (WMAP) is designed to produce all-sky maps of the cosmic microwave background (CMB) anisotropy. The WMAP 9-Year CMB-Free Point Source Catalog contained herein has information on 502 point sources in three frequency bands (41, 61 and 94 GHz, also known as the Q, V, and W bands, respectively) based on data from the entire 9 years of the WMAP sky survey from 10 Aug 2001 0:00 UT to 10 Aug 2010 0:00 UT, inclusive. The CMB-free method of point source identification was originally applied to one-year and three-year V- and W-band maps by Chen & Wright (2008, ApJ, 681, 747) and to five-year V- and W-band maps by Wright et al. (2009, ApJS, 180, 283). The method used here is that applied to five-year Q-, V-, and W-band maps by Chen & Wright (2009, ApJ, 694, 222) and to seven-year Q-, V-, and W-band maps by Gold et al. (2011, ApJS, 192, 15). The V- and W-band maps are smoothed to Q-band resolution. An internal linear combination (ILC) map (see Section 5.3.3 of the reference paper) is then formed from the three maps using weights such that CMB fluctuations are removed, flat-spectrum point sources are retained with fluxes normalized to Q-band, and the variance of the ILC map is minimized. The ILC map is filtered to reduce noise and suppress large angular scale structure. Peaks in the filtered map that are > 5 sigma and outside of the nine-year point source catalog mask are identified as point sources, and source positions are obtained by fitting the beam profile plus a baseline to the filtered map for each source. For the nine- year analysis, the position of the brightest pixel is adopted instead of the fit position in rare instances where they differ by > 0.1 degrees. Source fluxes are estimated by integrating the Q, V, and W temperature maps within 1.25 degrees of each source position, with a weighting function to enhance the contrast of the point source relative to background fluctuations, and applying a correction for Eddington bias due to noise (sometimes called "deboosting"). The authors identify possible 5-GHz counterparts to the WMAP sources found by cross-correlating with the GB6 (Gregory et al. 1996, ApJS, 103, 427), PMN (Griffith et al. 1994, ApJS, 90, 179; Griffith et al. 1995, ApJS, 97, 347; Wright et al. 1994, ApJS, 94, 111; Wright et al. 1996, ApJS, 103, 145), Kuehr et al. (1981, A&AS, 45, 367), and Healey et al. (2009, AJ, 138, 1032) catalogs. A 5-GHz source is identified as a counterpart if it lies within 11 arcminutes of the WMAP source position (the mean WMAP source position uncertainty is 4 arcminutes). When two or more 5 GHz sources are within 11 arcminutes, the brightest is assumed to be the counterpart and a multiple identification flag is entered in the catalog. A separate 9-year Point Source Catalog (available in Browse as the <a href="/W3Browse/wmap/wmapptsrc.html">WMAPPTSRC</a> table) has information on 501 point sources in five frequency bands from 23 to 94 GHz that were found using an alternative method. The two catalogs have 387 sources in common. As noted by Gold et al. (2011, ApJS, 192, 15), differences in the source populations detected by the two search methods are largely caused by Eddington bias in the five-band source detections due to CMB fluctuations and noise. At low flux levels, the five-band method tends to detect point sources located on positive CMB fluctuations and to overestimate their fluxes, and it tends to miss sources located in negative CMB fluctuations. Other point source detection methods have been applied to WMAP data and have identified sources not found by our methods (e.g., Scodeller et al. (2012, ApJ, 753, 27); Lanz (2012, ADASS 7); Ramos et al. (2011, A&A, 528, A75), and references therein). For more details of how the point source catalogs were constructed, see Section 5.2.2 of the reference paper. This table was last updated by the HEASARC in January 2013 based on an electronic version of Table 19 from the reference paper which was obtained from the LAMBDA web site, the file <a href="http://lambda.gsfc.nasa.gov/data/map/dr5/dfp/ptsrc/wmap_ptsrc_catalog_cmb_free_9yr_v5.txt">http://lambda.gsfc.nasa.gov/data/map/dr5/dfp/ptsrc/wmap_ptsrc_catalog_cmb_free_9yr_v5.txt</a>. The source_flag values of 'M' in this file were changed to the 'a' values that were used in the printed version of this table. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/wmapptsrc
- Title:
- WMAP Nine-Year Five-Band Point Source Catalog
- Short Name:
- WMAPPTSRC
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Wilkinson Microwave Anisotropy Probe (WMAP) is designed to produce all-sky maps of the cosmic microwave background (CMB) anisotropy. The WMAP 9-Year Point Source Catalog contained herein has information on point sources in five frequency bands from 23 to 94 GHz, based on data from the entire 9 years of the WMAP sky survey from 10 Aug 2001 0:00 UT to 10 Aug 2010 0:00 UT, inclusive. The 5-band search technique used in the first-year, 3-year, 5-year and 7-year analyses now finds 501 point sources, compared to 471 point sources found in the 7-year analysis and 390 sources found in the 5-year analysis. The 5-band search method is largely unchanged from the 7-year analysis (Gold et al. 2011, ApJS, 192, 15). This method searches for point sources in each of the five WMAP wavelength bands. The nine-year signal-to-noise ratio map in each band is filtered in harmonic space by b<sub>l</sub>/[(b<sub>l</sub>)<sup>2</sup> C<sub>l</sub>(cmb) + C<sub>l</sub>(noise)], where b<sub>l</sub> is the transfer function of the WMAP beam response, C<sub>l</sub>(cmb) is the CMB angular power spectrum, and C<sub>l</sub>(noise) is the noise power. The filtering suppresses CMB and Galactic foreground fluctuations relative to point sources. For each peak in the filtered maps that is > 5 sigma in any band, the unfiltered temperature map in each band is fit with the sum of a planar base level and a beam template formed by convolving an azimuthally symmetrized beam profile with a skymap pixel. (This method was previously used by Weiland et al. (2011, ApJS, 192, 19) for selected celestial calibration sources and is more accurate than the Gaussian fitting that was used for the seven-year and earlier point source analyses). The peak temperature from each beam template fit is converted to a source flux density using the conversion factor Gamma given in Table 3 of the reference paper. The flux density uncertainty is calculated from the 1-sigma uncertainty in the peak temperature, and does not include any additional uncertainty due to Eddington bias. Flux density values are entered into the catalog for bands where they exceed 2 sigma and where the source width from an initial Gaussian fit is within a factor of two of the beam width. A point source catalog mask is used to exclude sources in the Galactic plane and Magellanic cloud regions. This mask has changed from the seven-year analysis in accordance with changes in the KQ85 temperature analysis mask. A map pixel is outside of the nine-year point source catalog mask if it is either outside of the diffuse component of the nine-year KQ85 temperature analysis mask or outside of the seven-year point source catalog mask. The present mask admits 83% of the sky, compared to 82% and 78% for the previous 7-year and 5-year versions, respectively. The authors identify possible 5-GHz counterparts to the WMAP sources found by cross-correlating with the GB6 (Gregory et al. 1996, ApJS, 103, 427), PMN (Griffith et al. 1994, ApJS, 90, 179; Griffith et al. 1995, ApJS, 97, 347; Wright et al. 1994, ApJS, 94, 111; Wright et al. 1996, ApJS, 103, 145), Kuehr et al. (1981, A&AS, 45, 367), and Healey et al. (2009, AJ, 138, 1032) catalogs. A 5-GHz source is identified as a counterpart if it lies within 11 arcminutes of the WMAP source position (the mean WMAP source position uncertainty is 4 arcminutes). When two or more 5 GHz sources are within 11 arcminutes, the brightest is assumed to be the counterpart and a multiple identification flag is entered in the catalog. A separate 9-year CMB-free Point Source Catalog (available in Browse as the <a href="/W3Browse/wmap/wmapcmbfps.html">WMAPCMBFPS</a> table) has information on point sources in three frequency bands from 41 to 94 GHz: the CMB-free method identified 502 point sources in a linear combination map formed from 41, 61 and 94 GHz band maps using weights such that CMB fluctuations are removed and flat-spectrum point sources are retained. The two catalogs have 387 sources in common. As noted by Gold et al. (2011, ApJS, 192, 15), differences in the source populations detected by the two search methods are largely caused by Eddington bias in the five-band source detections due to CMB fluctuations and noise. At low flux levels, the five-band method tends to detect point sources located on positive CMB fluctuations and to overestimate their fluxes, and it tends to miss sources located in negative CMB fluctuations. Other point source detection methods have been applied to WMAP data and have identified sources not found by our methods (e.g., Scodeller et al. (2012, ApJ, 753, 27); Lanz (2012, ADASS 7); Ramos et al. (2011, A&A, 528, A75), and references therein). For more details of how the point source catalogs were constructed, see Section 5.2.2 of the reference paper. This table was last updated by the HEASARC in January 2012 based on an electronic version of Table 18 from the 2012 (ApJS, submitted) paper which was obtained from the LAMBDA web site, the file <a href="http://lambda.gsfc.nasa.gov/data/map/dr5/dfp/ptsrc/wmap_ptsrc_catalog_9yr_v5.txt">http://lambda.gsfc.nasa.gov/data/map/dr5/dfp/ptsrc/wmap_ptsrc_catalog_9yr_v5.txt</a>. The source_flag values were modified from those given in this file to reflect the values that were given in the printed version of the table. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/wmapitnpts
- Title:
- WMAP 7-Year Internal Templates and Needlets New Source Catalog
- Short Name:
- WMAPITNPTS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have developed a new needlet-based method to detect point sources in cosmic microwave background (CMB) maps and have applied it to the Wilkinson Microwave Anisotropy Probe (WMAP) 7-year data. They use both the individual frequency channels as well as internal templates, the latter being the difference between pairs of frequency channels and hence having the advantage that the CMB component is eliminated. Using the area of the sky outside the Kq85 galactic mask, they detect a total of 2102 point sources at the 5-sigma level in either the frequency maps or the internal templates. Of these, 1116 are detected either at 5 sigma directly in the frequency channels or at 5 sigma in the internal templates and >= 3 sigma at the corresponding position in the frequency channels. Of the 1116 sources, 603 are detections that have not been reported so far in WMAP data. The authors have made a catalog of these sources available with position and flux estimated in the WMAP channels where they are seen. In total, they identified 1029 of the 1116 sources with counterparts at 5 GHz and 69 at other frequencies. This table was created by the HEASARC in July 2012 based on an electronic version of Table 6 from the reference paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/woodebcat
- Title:
- Wood Interacting Binaries Catalog
- Short Name:
- Wood/Bin
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog, also called the Finding List (FL) of Interacting Binaries (5th edition), was abstracted from the Card Catalog maintained at the University of Florida which contains information on all published, and to the extent available, unpublished work on eclipsing binaries. The Card Catalog originated with Raymond Smith Dugan in the 1930's, who published from it the first edition of "A Finding List for Observers of Eclipsing Variables" (Dugan 1934, Princeton Univ. Obs. Contrib. No. 15). Successive editions of FL were subsequently published by Pierce (1947, Princeton Univ. Obs. Contrib. No. 22), by Wood (1953, Univ. Pennsylvania Astron. Series, Vol. VIII), by Koch et al. (1963, Univ. Pennsylvania Astron. Series, Vol. IX), and by Wood et al. (1980, Univ. Pennsylvania Astron. Series, Vol. XII). The FL was conceived as an aid to observers of eclipsing variables in selecting an observing program efficiently from the collection of all known data in an easy-to-use format. Although this format has changed over the years to meet existing requirements, the basic information content remains the same. The current edition differs from previous ones in the extension of the magnitude limit at minimum light from 13 to 15. In earlier editions, a binary system was not included unless the editors were reasonably certain that the system was indeed an eclipsing or (rarely) an ellipsoidal variable. The fifth edition includes all systems that the editors were fairly certain are either eclipsing or radiometrically variable binaries. The catalog fields are Finding List number; star name; position (given in the original catalog in equinox 1900); blue magnitude at maximum light; bandpass of maximum light; depth of primary minimum in same bandpass; bandpass primary minimum; depth of secondary minimum and its bandpass; spectral class of star eclipsed at primary light and optional uncertainty character; spectral class of star eclipsed at secondary light; most recent reliable epoch of primary minimum; most recent orbital period; duration of primary minimum; duration of totality of primary minimum; BD, CoD, CPD, and HD number; alternate designations of system; and codes indicating the nature of the system. This database was created by the HEASARC in December 1997 based on a computer readable version of the catalog that was obtained from the CDS (their catalog VI/44): a few additions were made by the HEASARC that are listed in the HEASARC_Changes section of the present document. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/woolley
- Title:
- Woolley Catalog of Stars within 25 Parsecs
- Short Name:
- WOOLLEY
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog was constructed at the Royal Greenwich Observatory in order to enlarge the Gliese (1957, Mitt. Astron. Rechen-Inst., Ser. A, No. 8) compilation. It contains data on stars nearer than 25 pc that were not included in that version of Gliese's catalog, plus some additional information that had been published after 1957 on stars which were present in the 1957 version of the Gliese catalog. The electronic version contains essentially all information given in Table Ia of the published Woolley catalog, plus positional data, and most cross references to other catalogs given in Table IIa. The notes flags in Table Ia are not included because the notes are not machine-readable. Omitted from Table IIa are the finding-chart indicators (Lowell G numbers or notes references) and miscellaneous cross identifications to other names and catalog identifiers. Tables Ib and IIb, containing 21 systems originally included in Gliese's (1957) catalog but for which revised parallaxes have placed them farther than 25 pc are not included in the electronic version. Data in the electronic version include the Gliese number (newly added stars by Woolley have numbers beginning with 9001, but new parallaxes have removed 9419 and added 9849 and 9850 from the < 25 parsecs sample), component identifications for multiple systems, parallaxes, annual proper motions, radial velocities, (U,V,W) space velocities, box orbit parameters (omega, e, i), spectral types, UBV data, absolute visual magnitudes, positions, GCTP (General Catalogue of Trigonometric Stellar Parallaxes) and its Supplement (Jenkins 1952, 1963) names, HD, DM, GCRV (General Catalogue of Stellar Radial Velocities, Publ. Carnegie Inst., Washington, No. 601, Wilson 1953) and other catalog identifiers, BS (= HR) (Hoffleit 1964) numbers, and remarks codes for spectroscopic binaries (SB), doubles, variables, etc. Note that there is an entry in this catalog for the Sun, for which many fields, such as RA and Dec, have not been populated. This table was recreated by the HEASARC in December 2002 based on the 21-Jul-1997 version of the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/V/32A">CDS Catalog V/32A</a>. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/wsrtgp
- Title:
- WSRT Galactic Plane Compact 327-MHz Source Catalog
- Short Name:
- WSRTGP
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Westerbork Synthesis Radio Telescope (WSRT) in the Netherlands has been used to survey the section of the galactic plane from +42 to +92 degrees Galactic Longitude l at a radio frequency of 327 MHz. Twenty-three overlapping synthesis fields were observed in the Galactic Latitude b band of |b| < 1.6 degrees. Each field was observed at two epochs, several years apart, to identify variable sources. Intensity data from the separate epochs were combined, and the resulting images mosaicked to produce a single image of the entire survey region. The sensitivity of the mosaic is typically a few mJy, corresponding to a detection level as low as 10 mJy/beam. The spatial resolution is 1' by 1' * cosec(Dec). The survey image provided the first high resolution view of the Galaxy at low radio frequencies, and included sections of the Sagittarius and Cygnus arms. These sections contain numerous extended features, among them supernova remnants, H II regions, "bubbles" of thermal emission, and large patches of amorphous galactic thermal emission. The inter-arm region is characterized by lower densities of extended features, but numerous discrete compact radio sources, most of which are background objects such as quasars and other types of active galactic nuclei. However, the resolution, sensitivity and low frequency of this survey make it ideal for detecting weak, non-thermal compact galactic sources, e.g. compact, low surface brightness SNRs and radio stars. Inspection of the survey image has produced a catalog of nearly 4000 discrete sources with sizes of less than about 3'. Gaussian model parameters for each compact source in the mosaicked images were obtained using the AIPS routine IMFIT. The background-removed intensity distribution of each source was fitted by a 2-dimensional Gaussian, parametrized by the source position, peak intensity, major and minor axes, and the position angle of the major axis. The catalog contains all sources having peak intensity > 5 times the rms noise level measured in the surrounding area of the image, and lists RA, Dec, flux density, and, if the source is resolved, the deconvolved major and minor axis and the position angle of the source. Sources were identified based on visual inspection of the images. In practice, a source had to have dimensions of less than a few arcminutes to be classified as a compact source. Most (85%) of the sources are either unresolved or only slightly resolved (major axis < 60"), but some sources have dimensions as large as 6'. A source was considered resolved if the area of its Gaussian model was greater than the area of the beam by more than 4 times its uncertainty. Approximately 15% of the sources are resolved, with dimensions of 1'- 3'. The spatial distribution of resolved sources shows concentrations toward the spiral arms and follows the warping of the Galactic disk over the length of the survey region, indicating that a sizable fraction is Galactic. In the reference paper, spectral indices are calculated for 1313 sources detected in other radio surveys at frequencies greater than 408 MHz. The resolved sources exhibit a bimodal spectral index distribution, with distinct non-thermal and thermal populations. Comparison with the IRAS Point Source Catalogue results in 118 identifications between WSRT and IRAS sources, which are listed in Table 1 of the reference paper. Most of these are thermal radio sources associated with compact Galactic objects such as H II regions and planetary nebulae. A search for variability among 2148 of the compact sources has resulted in 29 candidate low-frequency variable sources, which are listed in Table 2 of the reference paper. See the project website at <a href="http://www.ras.ucalgary.ca/wsrt_survey.html">http://www.ras.ucalgary.ca/wsrt_survey.html</a> for the WSRTGP images available in JPEG, PostScript, and FITS formats. This table was created by the HEASARC in February 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/107/239">CDS Catalog J/ApJS/107/239</a> file wsrt.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/w40sfrcxo
- Title:
- W 40 Star-Forming Region Chandra X-Ray Point Source Catalog
- Short Name:
- W40SFRCXO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The young stellar cluster illuminating the W40 H II region, one of the nearest massive star-forming regions (SFRs), has been observed with the ACIS detector on board the Chandra X-ray Observatory. Due to its high obscuration, this is a poorly studied stellar cluster with only a handful of bright stars visible in the optical band, including three OB stars identified as primary excitation sources. The authors detect 225 X-ray sources, of which 85% are confidently identified as young stellar members of the region. Two potential distances of the cluster, 260 pc and 600 pc, are used in the paper. Supposing the X-ray luminosity function of SFRs to be universal, it supports a 600 pc distance as a lower limit for W40 and a total population of at least 600 stars down to 0.1 M<sub>sun</sub> under the assumption of a coeval population with a uniform obscuration. In fact, there is strong spatial variation in K<sub>s</sub>-band-excess disk fraction and non-uniform obscuration due to a dust lane that is identified in absorption in optical, infrared, and X-ray. The dust lane is likely part of a ring of material which includes the molecular core within W40. In contrast to the likely ongoing star formation in the dust lane, the molecular core is inactive. The star cluster has a spherical morphology, an isothermal sphere density profile, and mass segregation down to 1.5 M<sub>sun</sub>. However, other cluster properties, including a <= 1 Myr age estimate and ongoing star formation, indicate that the cluster is not dynamically relaxed. X-ray diffuse emission and a powerful flare from a young stellar object are also reported in the reference paper. This table was created by the HEASARC in March 2011 based on electronic versions of Tables, 1, 2 and 4 of the reference paper which were obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/xbootesoid
- Title:
- XBOOTES:NDWFSBootesFieldOptical&NearIRCounterparts
- Short Name:
- XBOOTESOID
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The XBootes Survey is a 5 ks Chandra survey of the Bootes Field of the NOAO Deep Wide-Field Survey (NDWFS). This survey is unique in that it is the largest (9.3 square degrees) contiguous region imaged in X-ray with complementary deep optical and near-infrared (near-IR) observations. The authors present a catalog of the optical counterparts to the 3213 X-ray point sources detected in the XBootes survey. Using a Bayesian identification scheme, they successfully identified optical counterparts for 98% of the X-ray point sources. The optical colors suggest that the optically detected galaxies are a combination of z < 1 massive early-type galaxies and bluer star-forming galaxies whose optical AGN emission is faint or obscured, whereas the majority of the optically detected point sources are likely quasars over a large redshift range. This large-area, X-ray-bright, optically deep survey enables the authors to select a large subsample of sources (773) with high X-ray to optical flux ratios (f<sub>X</sub>/f<sub>o</sub> > 10). These objects are likely high-redshift and/or dust-obscured AGNs. These sources have generally harder X-ray spectra than sources with 0.1 < f<sub>X</sub>/f<sub>o</sub> < 10. Of the 73 X-ray sources with no optical counterpart in the NDWFS catalog, 47 are truly optically blank down to R ~ 25.5 (the average 50% completeness limit of the NDWFS R-band catalogs). These sources are also likely to be high-redshift and/or dust-obscured AGNs. The 9.3 square degrees region of sky chosen to match the area covered with the NDWFS was observed by ACIS-I on the Chandra X-Ray Observatory over a 2 week time interval in 2003 March and April. The data were taken in 126 separate pointings, each observed for ~ 5 ks. The CIAO 3.0.2 wavelet detection algorithm (wavdetect; Freeman et al. 2002) was used to detect X-ray sources in the total (0.5 - 7.0 keV) band data. A probability threshold of 5 x 10-5 was chosen as the best compromise between maximizing the completeness while minimizing the number of spurious detections. The X-ray catalog comprises 3293 unique X-ray sources with >= 4 counts in the total-band images (Paper II). The authors expect only ~ 35 of these sources to be spurious in the full survey (Paper II). For the matching with cataloged optical counterparts, the authors only considered the 3213 X-ray sources that overlap with the NDWFS area. The authors include all multiply matched sources with >1% probability of being the correct optical counterpart. This table contains the X-ray and optical characteristics of the matched optical/X-ray catalog for the Chandra sources in the XBootes and NDWFS survey, and is Version 1.0, dated 21st June 2005. This table was created in November 2006 by the HEASARC based on the file xbootes_cat_xray_opt_IR_21jun_v1.0.txt obtained from the NOAO ftp area <a href="https://www.noao.edu/noao/noaodeep/XBootesPublic/">https://www.noao.edu/noao/noaodeep/XBootesPublic/</a>. This is a service provided by NASA HEASARC .
