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11. Akari North Ecliptic Pole Deep Field Chandra X-Ray Point Source Catalog
ID:
ivo://nasa.heasarc/aknepdfcxo
Title:
Akari North Ecliptic Pole Deep Field Chandra X-Ray Point Source Catalog
Short Name:
AKNEPDFCXO
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains results from the 300-ks Chandra survey in the AKARI North Ecliptic Pole (NEP) deep field. This field has a unique set of 9-band infrared photometry covering 2-24 micron from the AKARI Infrared Camera, including mid-infrared (MIR) bands not covered by Spitzer. The survey is one of the deepest ever achieved at ~15 micron, and is by far the widest among those with similar depths in the MIR. This makes this field unique for the MIR-selection of AGN at z ~1. The authors have designed a source detection procedure, which performs joint Maximum Likelihood PSF fits on all of their 15 mosaicked Chandra pointings covering an area of 0.34 square degrees. The procedure has been highly optimized and tested by simulations. A point source catalog with photometry and Bayesian-based 90%-confidence upper limits in the 0.5-7, 0.5-2, 2-7, 2-4, and 4-7 keV bands has been produced. The catalog contains 457 X-ray sources and the spurious fraction is estimated to be ~1.7%. Sensitivity and 90%-confidence upper flux limits maps in all bands are provided as well. In their study, the authors searched for optical MIR counterparts in the central 0.25 square degrees, where deep Subaru Suprime-Cam multi-band images exist. Among the 377 X-ray sources detected therein, ~80% have optical counterparts and ~60% also have AKARI mid-IR counterparts. The authors cross-matched their X-ray sources with MIR-selected AGN from Hanami et al. (2012, PASJ, 64, 70). Around 30% of all AGN that have MID-IR SEDs purely explainable by AGN activity are strong Compton-thick AGN candidates. The source catalog contained in this table uses an internal threshold of ML = 9.5 which corresponds to ML<sub>empir</sub> ~12 (see Sect. 4.3.3 of the reference paper for more details). In total, 457 sources are detected, of which 377 objects fall in the deep Subaru imaging region (shown in Figure 1 of the reference paper). This catalog is designed to identify X-ray emitting objects in the Chandra/AKARI NEP deep field. Together with the optimized cross-identification procedure, the clear advantage of the catalog is the very high reliability, while the catalog sacrifices completeness for objects with low counts (see Figure 9 in the paper). Only ~1.7% of the objects listed in the source catalog are expected to be spurious source detections. The two sources that have an ML-threshold in the 0.5-7 keV band below 9.5 originate from a 0.5-7 keV single-band source detection run. To quote similar ML values for all objects, the authors list the total 0.5-7 keV ML values from the joint 3-energy band source detection run. The listed counts, count rates, fluxes, and the corresponding uncertainties in the 0.5-7 keV band are taken from the single-band detection run. Considering the uncertainty in the astrometric calibration, all sources should be considered as possible X-ray counterparts that are within a radius of r<sub>match</sub> = sqrt(sigma<sub>total</sub><sup>2</sup>+sigma<sub>astro</sub><sup>2</sup>), with sigma<sub>total</sub> = 5 * sqrt(sigma<sub>sys</sub><sup>2</sup>+sigma<sub>stat</sub><sup>2</sup>) and sigma<sub>sys</sub> = 0.1 arcseconds and sigma<sub>astro</sub> = 0.2 arcseconds (astrometric uncertainty). The authors also created a low-probability source catalog (not contained in this present HEASARC table): they caution that, due to the significant number of spurious sources in the low-probability catalog, it should NOT be used to select X-ray sources or to increase the sample size of X-ray-selected objects. It can be of interest if the scientific goal requires one to EXCLUDE potential X-ray emitting objects from a sample with a high completeness, since, using this strategy, one accepts those objects that are excluded are not associated with an X-ray-emitting object. The low-probability source catalog (available at <a href="http://cdsarc.u-strasbg.fr/ftp/cats/J_MNRAS/446/911/">http://cdsarc.u-strasbg.fr/ftp/cats/J_MNRAS/446/911/</a> as the files lowpscat.dat.gz and lowpscat.fits) has a lower maximum likelihood threshold than the main source catalog (an internal threshold of ML = 5, corresponding to ML<sub>empir</sub> ~9.5). This catalog contains 626 detected sources, of which 506 are located within the deep Subaru imaging region. Based on their simulated data, the authors conclude that 19% of all the low-probability source catalog entries are false detections. Considering only the deep Subaru imaging area the spurious source fraction drops to 15%. When using information from this catalog, please cite the reference paper: Krumpe et al. (2015, MNRAS, 446, 911). This table was created by the HEASARC in August 2015 based on CDS table J/MNRAS/446/911 files mainscat.dat, the main source catalog. 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 .
12. Allen Telescope Array Pi GHz Sky Survey (PiGSS) Boo Field Source Catalog
ID:
ivo://nasa.heasarc/pigssboofd
Title:
Allen Telescope Array Pi GHz Sky Survey (PiGSS) Boo Field Source Catalog
Short Name:
PIGSSBOOFD
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The Pi GHz Sky Survey (PiGSS) is a key project of the Allen Telescope Array (ATA). PiGSS is a 3.1 GHz survey of radio continuum emission in the extragalactic sky with an emphasis on synoptic observations that measure the static and time-variable properties of the sky. During the 2.5 year campaign, PiGSS will twice observe ~250,000 radio sources in the 10,000 deg<sup>2</sup> region of the sky with b > 30 degrees to an rms sensitivity of ~1 mJy. Additionally, sub-regions of the sky will be observed multiple times to characterize variability on timescales of days to years. Presented here are the results from observations of a 10 deg<sup>2</sup> region in the Bootes constellation overlapping the NOAO Deep Wide Field Survey field. The PiGSS image was constructed from 75 daily observations distributed over a 4 month period and has an rms flux density between 200 and 250 µJy. This represents a deeper image by a factor of 4-8 than the authors will achieve over the entire 10,000 deg<sup>2</sup>. In this table, they provide flux densities, source sizes, and spectral indices for the 425 sources detected in the image. They identify ~100 new flat-spectrum radio sources, and project that, when completed, PiGSS will identify 104 flat-spectrum sources. In their paper the authors identify one source that is a possible transient radio source. This survey provides new limits on faint radio transients and variables with characteristic durations of months. This table was created by the HEASARC in March 2011 based on electronic versions of Tables 2 and 4 from the reference paper which were obtained from the ApJ web site. The HEASARC changed the sign of the values of the last parameter in Table 4 (herein called spectral_index_3_error) from negative to positive. In March 2013, after receiving a clarification from Steve Croft, the HEASARC corrected the names of the 4 parameters describing the source sizes (to reflect the fact that they were diameters nor radii) to major_axis, minor_axis, fit_major_axis and fit_minor_axis. This is a service provided by NASA HEASARC .
13. Allen Telescope Array Pi GHz Sky Survey (PiGSS) Deep Fields Source Catalog
ID:
ivo://nasa.heasarc/pigsselcnf
Title:
Allen Telescope Array Pi GHz Sky Survey (PiGSS) Deep Fields Source Catalog
Short Name:
PIGSSELCNF
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains results from a total of 459 repeated 3.1-GHz radio continuum observations (of which 379 were used in a search for transient sources) of the ELAIS-N1, Coma, Lockman Hole, and NOAO Deep Wide Field Survey (NDWFS) fields as part of the Allen Telescope Array (ATA) Pi GHz Sky Survey (PiGSS). The observations were taken in 2 simultaneous 100-MHz wide bands centered at 3.04 and 3.14 GHz approximately once per day between 2009 May and 2011 April. Each image covers 11.8 square degrees and has 100" FWHM resolution. Deep images for each of the four fields have rms noise between 180 and 310 µJy (µJy), and the corresponding catalogs contain ~200 sources in each field. Typically 40-50 of these sources are detected in each single-epoch image. This represents one of the shortest cadence, largest area, multi-epoch surveys undertaken at these frequencies. The authors compared the catalogs generated from the combined images to those from individual epochs, and from monthly averages, as well as to legacy surveys. They undertook a search for transients, with particular emphasis on excluding false positive sources,but find no confirmed transients, defined here as sources that can be shown to have varied by at least a factor of 10. However, the authors found one source that brightened in a single-epoch image to at least six times the upper limit from the corresponding deep image. They also found a source associated with a z = 0.6 quasar which appears to have brightened by a factor ~3 in one of their deep images, when compared to catalogs from legacy surveys. The authors place new upper limits on the number of transients brighter than 10 mJy: fewer than 0.08 transients deg<sup>-2</sup> with characteristic timescales of months to years; fewer than 0.02 deg<sup>-2</sup> with timescales of months; and fewer than 0.009 deg<sup>-2</sup> with timescales of days. In this study, the authors accepted only as real sources those that are independently detected in both frequencies in at least one epoch (with a position matching tolerance of 50", corresponding to a false match probability of <2%). Their threshold of ~ 4.2 sigma for detection in a single image corresponds to a threshold of ~ 5.9 sigma in the dual-image catalog. They generated catalogs for the deep fields, consisting only of sources detected at both frequencies, and these are contained in the present HEASARC table. Notice that the authors previously published a list of 425 radio sources in the NDWFS field in the constellation of Bootes in an earlier paper (Bower et al 2010, ApJ, 725, 1792, available as the HEASARC database table PIGSSBOOFD). In the 2013 paper, they have performed a partial re-analysis of these data to conform with the updated analysis techniques used on the other three fields. This table was created by the HEASARC in March 2013 based on electronic versions of Tables 2, 3, 4 and 5 (source lists for each of the 4 fields, ELAIS N1, Lockman, Coma, and NDWFS, respectively) from the reference paper which were obtained from the ApJ web site. The HEASARC has created a new parameter called field_name which identifies in which table/field the source can be found. Thus, to select only sources in the Lockman Hole field, the user should select field_name= 'Lockman'. This is a service provided by NASA HEASARC .
14. Allen Telescope Array Twenty-cm Survey (ATATS) Source Catalog
ID:
ivo://nasa.heasarc/atats
Title:
Allen Telescope Array Twenty-cm Survey (ATATS) Source Catalog
Short Name:
ATATS
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains the source catalog from the Allen Telescope Array Twenty-centimeter Survey (ATATS), a multi-epoch (12 visits), 690 deg<sup>2</sup> radio image and catalog at 1.4 GHz. The survey is designed to detect rare, very bright transients as well as to verify the capabilities of the ATA to form large mosaics. The combined image using data from all 12 ATATS epochs has an rms noise sigma = 3.94 mJy beam<sup>-1</sup> and a dynamic range of 180, with a circular beam of 150 arcseconds FWHM. It contains 4408 sources to a limiting sensitivity of 5 sigma = 20 mJy beam<sup>-1</sup>. The authors compare the catalog generated from this 12-epoch combined image to the NRAO VLA Sky Survey (NVSS), a legacy survey at the same frequency, and find that they can measure source positions to better than ~ 20 arcseconds. For sources above the ATATS completeness limit, the median flux density is 97% of the median value for matched NVSS sources, indicative of an accurate overall flux calibration. The authors examine the effects of source confusion due to the effects of differing resolution between the ATATS and NVSS on their ability to compare flux densities. They detect no transients at flux densities greater than 40 mJy in comparison with NVSS and place a 2 sigma upper limit of 0.004 deg<sup>-2</sup> on the transient rate for such sources. These results suggest that the >~ 1 Jy transients reported by Matsumara et al. (2009, AJ, 138, 787) may not be true transients, but rather variable sources at their flux density threshold. This table was created by the HEASARC in September 2010 based on the electronic version of Table 2 from the reference paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
15. All-Sky Automatic Survey (ASAS) Photometry of ROSAT All-Sky Survey Sources
ID:
ivo://nasa.heasarc/rassasaspv
Title:
All-Sky Automatic Survey (ASAS) Photometry of ROSAT All-Sky Survey Sources
Short Name:
RASSASASPV
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
Photometric data from the All-Sky Automatic Survey (ASAS) - South (Declination less than 29 degrees) Survey have been used for the identification of bright stars located near the sources from the ROSAT All Sky Survey Bright Source Catalog (RASSBSC). In total, 6,028 stars brighter than 12.5 magnitude in the I- or the V-bands have been selected and analyzed for periodicity. Altogether, 2,302 variable stars have been found with periods ranging from 0.137 days to 193 days. Most of these stars have X-ray emission of coronal origin, but there are a few cataclysmic binaries and early type stars with colliding winds. Whenever it was possible, the authors collected data available in the literature so as to verify the periods and to classify variable objects. The catalog includes 1,936 stars (1,233 new) considered to be variable due to presence of spots (rotationally variable), 127 detached eclipsing binary stars (33 new), 124 contact binaries (11 new), 96 eclipsing stars with deformed components (19 new), 13 ellipsoidal variables (4 new), 5 miscellaneous variables and one pulsating RR Lyr type star (blended with an eclipsing binary). More than 70% of the new variable stars have amplitudes smaller than 0.1 magnitudes, but for the star ASAS 063656-0521.0 the authors have found the largest known amplitude of brightness variations due to the presence of spots (up to Delta V = 0.8 magnitudes). This table was created by the HEASARC in May 2018, based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AcA/62/67">CDS Catalog J/AcA/62/67</a> files catalog.dat and remarks.dat. This is a service provided by NASA HEASARC .
16. All-Sky Catalog of Faint EUV Sources
ID:
ivo://nasa.heasarc/euvexrtcat
Title:
All-Sky Catalog of Faint EUV Sources
Short Name:
EUV/Faint
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The All-Sky Catalog of Faint Extreme-Ultraviolet (EUV) Sources is a list of 534 objects detected jointly in the Extreme Ultraviolet Explorer (EUVE) (100 Angstrom (AA) band) All-Sky Survey and in the ROSAT X-ray Telescope (XRT) (0.25 keV band) All-Sky Survey. The joint selection criterion within a 1.5 arcminute positional tolerance permitted the use of a low count rate threshold in each survey. This low threshold was roughly 60% of the threshold used in the previous EUVE all-sky surveys, and 166 of the objects listed in this table were new EUV sources, appearing neither in the Second EUVE Source Catalog nor in the ROSAT Wide Field Camera Second Catalog. Preliminary identifications are offered for 105 of the 166 sources not previously reported in any EUV catalog: by far the most numerous (81) of the identifications are late-type (F-M) stars, while 18 are other stellar types, only 5 are white dwarfs, and none are extragalactic. The paucity of WDs and extragalactic objects may be explained by a strong horizon effect wherein interstellar absorption strongly limits the effective new-source search volume, and, thereby, selectively favors low-luminosity nearby sources over more luminous but distant objects. Notice that, with the adopted 1.5 arcminute acceptance criterion, about 50 spurious detections are expected. This Browse table was created in July 2003 based on CDS table IX/35/faint.dat. This is a service provided by NASA HEASARC .
17. All-Sky Optical Catalog of Radio/X-Ray Sources
ID:
ivo://nasa.heasarc/qorgcat
Title:
All-Sky Optical Catalog of Radio/X-Ray Sources
Short Name:
QuasarOrg
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The Quasars.org (QORG) Catalog is an all-sky optical catalog of radio/X-ray sources. The QORG Catalog aligns and overlays the year 2001/2 releases of the ROSAT HRI, RASS, PSPC and WGA X-ray catalogs, the NVSS (2002), FIRST (2003) and SUMSS (2003) radio catalogs, the Veron QSO catalog (2003) and various galaxy/star reference catalogs onto the optical APM and USNO-A catalogs. This catalog displays calculated percentage probabilities for each optical, radio/X-ray associated object of its likelihood of being a quasar, galaxy, star, or erroneous radio/X-ray association. This table contains the main Master QORG catalog (master.dat) and contains all 501,756 radio/X-ray associated optical objects and known quasars which are optically detected in APM/USNO-A. Up to six radio/X-ray catalog identifications are presented for each optical object, plus any double radio lobes (21,498 of these). These are superimposed (and laterally fitted) onto a 670,925,779-object optical background which combines APM and USNO-A data. Other subsets of this master catalog are available at the CDS, including the Free-Lunch catalog, a concise easy-to-read variant of the Master catalog showcasing just one X-ray and/or radio identification for each object, a subset catalog of QSO candidates, and a subset catalog of known QSOs/galaxies/stars. Objects presented in this catalog are those optical APM/USNO-A objects which are associated with X-ray/radio detections, or any optically-found catalogued QSO/AGN/Bl Lac objects, which have confidence levels >40% of being radio/X-ray emitting optical objects. There are 501,756 objects included in all (including 48,285 catalogued quasars), representing the 99.4% coverage of the sky which is available from the APM and USNO-A. Each object is shown as one entry giving the position in equatorial coordinates, red and blue optical magnitudes (recalibrated) and PSF class, calculated probabilities of the object being, separately, a quasar, galaxy, star, or erroneous radio/X-ray association, any radio identification from each of the NVSS, FIRST and SUMSS surveys, including candidate double-lobe detections, any X-ray identification from each of the ROSAT HRI, RASS, PSPC and WGA surveys, including fluxes and field shifts of those identifications, plus, if already catalogued, the object name and redshift where applicable. The QORG catalog and supporting data can be accessed from the catalog home page at <a href="http://quasars.org/qorg-data.htm">http://quasars.org/qorg-data.htm</a> Questions or comments on the catalog contents may be directed to the first author Eric Flesch at eric@flesch.org. The authors request that researchers using this catalog make a small acknowledgement of such use in any published papers which thereby result. This table was created by the HEASARC in November 2004 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/427/387">CDS Catalog J/A+A/427/387</a> file master.dat.gz. This is a service provided by NASA HEASARC .
18. All-Wavelength Extended Groth Strip Int. Survey (AEGIS) 20-cm Fully Id-ed Sample
ID:
ivo://nasa.heasarc/aegis20id
Title:
All-Wavelength Extended Groth Strip Int. Survey (AEGIS) 20-cm Fully Id-ed Sample
Short Name:
AEGIS20ID
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
Infrared 3.6 - 8.0 micron (µm) images of the Extended Groth Strip (EGS) yield plausible counterpart identifications for all but one of 510 radio sources in the AEGIS20 S(1.4 GHz) > 50 microJansky (µJy) sample (Ivison et al. 2007, ApJ, 660, L77, available at the HEASARC as the AEGIS20 database table). This is the first such deep sample that has been effectively 100% identified. Achieving the same identification rate at R band would require observations reaching R<sub>AB</sub> > 27. Spectroscopic redshifts are available for 46% of the sample and photometric redshifts for an additional 47%. Almost all of the sources with 3.6-um AB magnitudes brighter than 19 have spectroscopic redshifts z < 1.1, while fainter objects predominantly have photometric redshifts with 1 <~ z <~ 3. Unlike more powerful radio sources that are hosted by galaxies having large stellar masses within a relatively narrow range, the AEGIS20 counterparts have stellar masses spanning more than a factor of 10 at z ~ 1. The sources are roughly 10% - 15% starbursts at z <~ 0.5 and 20%-25% active galactic nuclei mostly at z > 1, with the remainder of uncertain nature. Throughout this study, magnitudes are in the AB system, and the notation [w] means the AB magnitude at wavelength w in um. Source distances are based on standard Lambda-CDM cosmology with H<sub>0</sub> = 71 km s<sup>-1</sup> Mpc<sup>-1</sup> and Omega<sub>M</sub> = 0.27. Practical calculation of luminosity distances was based on the program ANGSIX (Kayser et al. 1997, A&A, 318, 680). This table was created by the HEASARC in July 2013 based on the electronic versions of Tables 1, 3, 4, and 5 from the reference paper which were obtained from the ApJ web site. This is a service provided by NASA HEASARC .
19. All-Wavelength Extended Groth Strip Int. Survey (AEGIS) VLA 20-cm Source Catalog
ID:
ivo://nasa.heasarc/aegis20
Title:
All-Wavelength Extended Groth Strip Int. Survey (AEGIS) VLA 20-cm Source Catalog
Short Name:
AEGIS20
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains results from AEGIS20, a radio survey of the Extended Groth Strip (EGS) conducted with the Very Large Array (VLA) at a frequency of 1.4 GHz. The resulting catalog contains 1122 emitters (HEASARC Note: The abstract of the original reference paper said 1123, but as noted by Willner et al. (2012, ApJ, 756, 72: footnote 10, one entry ('EGS20 J142303.7+532224.5') was listed twice in the original catalog), and it is sensitive to ultraluminous (10<sup>12</sup> solar luminosities) starbursts to z <= 1.3, well matched to the redshift range of the DEEP2 spectroscopic survey in this region. The authors use stacking techniques to explore the microJansky-level emission from a variety of galaxy populations selected via conventional criteria - Lyman break galaxies (LBGs), distant red galaxies (DRGs), UV-selected galaxies, and extremely red objects (EROs) - determining their properties as a function of color, magnitude, and redshift and their extinction-free contributions to the history of star formation. This study confirms the familiar pattern that the star formation rate (SFR) density, increases by at least a factor of ~ 5 from z = 0 to 1, although the authors note highly discrepant UV- and radio-based SFR estimates. Their radio-based SFRs become more difficult to interpret at z > 1 where correcting for contamination by radio-loud active galactic nuclei (AGNs) comes at the price of rejecting luminous starbursts. While stacking radio images is a useful technique, accurate radio-based SFRs for z >> 1 galaxies require precise redshifts and extraordinarily high fidelity radio data to identify and remove accretion-related emission. Data were obtained at 1.4 GHz during 2003 to 2005 with the VLA in its B configuration, acquiring seven 3.125 MHz channels every 5 s at each of four intermediate frequencies. Data were obtained at six positions, spaced by 15 arcminutes, concentrating in the northern half of the EGS because of the proximity of 3C 295 (a 23 Jy source at 1.4 GHz). Around 18 hours of data were acquired for each of the field positions. Calibrated visibilities and associated weights were used to generate mosaics of 37 x 512<sup>2</sup> x 0.8 arcsec<sup>2</sup> pixel images to quilt the VLA's primary beam in each EGS field position. CLEAN boxes were placed tightly around all sources, and a series of IMAGR and CALIB tasks were run, clipping the UV data after subtracting CLEAN components generated by the third iteration of IMAGR. The central images from each of the pointings were then knitted together using FLATN, ignoring data beyond the primary beam's half-power point, to produce a large mosaic. The synthesized beam is circular, with a FWHM of ~ 3.8 arcseconds. To define a sample of radio sources, the authors searched signal-to-noise ratio (S/N) images using the SAD detection algorithm, emulating the technique described by Biggs & Ivison (2006, MNRAS, 371, 963). Sources with >= 4-sigma peaks were fitted with two-dimensional Gaussians using JMFIT, and those with >- 5-sigma peaks that survived were fitted in total intensity. Sources with sizes equal to or smaller than the restoring beam were considered unresolved. No correction is made for bandwidth smearing in the catalog; this is a small effect (~ 5%) given the mosaicking strategy and the use of the B configuration. 38, 79, 171, 496, and 1123 sources are detected with 1.4 GHz flux densities >= 2000, >= 800, >= 320, >= 130 and >= 50 microJansky (µJy) [including the duplicate source mentioned above], where the 5-sigma detection limits at 130 and 50 uJy cover 0.73 and 0.04 deg<sup>2</sup>, respectively. Confusion is not an issue; the source density on an arcmin<sup>2</sup> scale is < 0.01 beam<sup>-1</sup>. This table was created by the HEASARC in July 2013 based on an electronic versions of the catalog described in the reference paper which was obtained as a FITS file from the first author's web site at <a href="http://www.roe.ac.uk/~rji/aegis20/">http://www.roe.ac.uk/~rji/aegis20/</a>. This is a service provided by NASA HEASARC .
20. AllWISE Catalog of Mid-IR AGNs
ID:
ivo://nasa.heasarc/allwiseagn
Title:
AllWISE Catalog of Mid-IR AGNs
Short Name:
ALLWISEAGN
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains an all-sky sample of ~1.4 million active galactic nuclei (AGNs) meeting a two-color infrared photometric selection criterion for AGNs as applied to sources from the Wide-field Infrared Survey Explorer final catalog release (AllWISE). The authors assess the spatial distribution and optical properties of their sample and find that the results are consistent with expectations for AGNs. These sources have a mean density of ~38 AGNs per square degree on the sky, and their apparent magnitude distribution peaks at g ~ 20, extending to objects as faint as g ~ 26. The authors test the AGN selection criterion against a large sample of optically identified stars and determine the "leakage" (that is, the probability that a star detected in an optical survey will be misidentified as a quasi-stellar object (QSO) in their sample) rate to be <= 4.0 x 10<sup>-5</sup>. They conclude that their sample contains almost no optically identified stars (<= 0.041%), making this sample highly promising for future celestial reference frame work as it significantly increases the number of all-sky, compact extragalactic objects. The authors further compare their sample to catalogs of known AGNs/QSOs and find a completeness value of >= 84% (that is, the probability of correctly identifying a known AGN/QSO is at least 84%) for AGNs brighter than a limiting magnitude of R <= 19. This sample includes approximately 1.1 million previously uncataloged AGNs. The WISE survey is an all-sky mid-IR survey at 3.4, 4.6, 12, and 22 microns (W1, W2, W3, and W4, respectively) conducted between 2010 January 7 and August 6, during the cryogenic mission phase, and first made available to the public on 2011 April 14. WISE has angular resolutions of 6.1, 6.4, 6.5, and 12.0 arcseconds in its four bands, respectively. The AllWISE data release, which was used for this work, incorporates data from the WISE Full Cryogenic, 3-Band Cryo, and NEOWISE Post-Cryo survey (Mainzer et al. 2014, ApJ, 792, 30) phases, which were co-added to achieve a depth of coverage ~0.4 mag deeper than previous data releases. AllWISE contains the positions, apparent motions, magnitudes, and point-spread function (PSF)-profile fit information for almost 748 million objects. Astrometric calibration of sources in the WISE catalog was done by correlation with bright stars from the 2MASS point source catalog, and the astrometric accuracy for sources in the AllWISE release was further improved by taking into account the proper motions of these reference stars, taken from the fourth USNO CCD Astrograph Catalog (UCAC4, Zacharias et al. 2013, AJ, 145, 44). A comparison with ICRF sources shows that AllWISE Catalog sources in the brightness range of 8 < W1 < 12 mag have positional accuracies to within 50 mas, and half of these sources have positional accuracies to within 20 mas. For more details on the WISE mission, see Wright et al. (2010, AJ, 140, 1868). The authors took all sources from the AllWISE catalog following Equations (3) and (4) from Mateos et al. (2012, MNRAS, 426, 3271) and they require that all of their sources have S/N >= 5 in the first three bands, as recommended in Mateos et al. (2012); as a further constraint, they limit their results to those with cc_flags = "0000," meaning that the sources are unaffected by known artifacts such as diffraction spikes, persistence, halos, or optical ghosts. In order to characterize the optical properties of their sample, the authors cross-matched it to SDSS-DR12, which is the final data release of SDSS-III (Eisenstein et al. 2011, AJ, 142, 72), within a radial tolerance of R < 1", obtaining 424,366 matches. To determine the fraction of false positive positional matches (that is, incorrectly correlating an object in their sample with a different SDSS object due to random positional agreement), they performed the same match on a scrambled version of their sample coordinates, determining that less than 1% of other cross-matches are false positive positional matches between the two catalogs. The authors also cross-matched their sample sources with he second release of the Large Quasar Astrometric Catalog (LQAC-2; Souchay et al. 2012, A&A, 537, A99), which contains 187,504 quasars, including radio-selected quasars from the ICRF2, optically selected quasars from SDSS, and infrared-selected quasars from 2MASS, and thus represents a robust sample of quasars over a wide range of wavelengths. They find that 93,403 quasars from LQAC-2 have clean detections. The majority of non-detections are due to sources in LQAC-2 that are too faint, having R >~ 19. This table was created by the HEASARC in January 2016 based on the machine-readable version of Table 1 from the reference paper which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .