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AT20G/Fermi 1FGL Source Catalog
The high-frequency radio sky, like the gamma-ray sky surveyed by the Fermi satellite, is dominated by flat-spectrum radio quasars and BL Lac objects at bright flux levels. To investigate the relationship between radio and gamma-ray emission in extragalactic sources, the authors have cross-matched the Australia Telescope 20-GHz survey catalog (AT20G: Murphy et al. 2010, MNRAS, 402, 2403, available as a HEASARC Browse table) with the Fermi-LAT 1-year Point Source Catalog (1FGL: Abdo et al. 2010, ApJS, 188, 405, also available as the HEASARC Browse table FERMILPSC). The 6.0 sr of sky covered by both catalogs (Declination < 0 degrees, |b| > 1.5 degrees) contains 5890 AT20G radio sources and 604 1FGL gamma-ray sources. The AT20G source positions are accurate to within ~1 arcsec and, after excluding known Galactic sources, 43% of Fermi 1FGL sources have an AT20G source within the 95% Fermi confidence ellipse. Monte Carlo tests imply that at least 95% of these matches are genuine associations. Only five gamma-ray sources (1% of the Fermi catalog) have more than one AT20G counterpart in the Fermi error box. The AT20G matches also generally support the active galactic nucleus (AGN) associations in the First LAT AGN Catalog. The authors find a trend of increasing gamma-ray flux density with 20 GHz radio flux density. The Fermi detection rate of AT20G sources is close to 100% for the brightest 20 GHz sources, decreasing to 20% at 1 Jy, and to roughly 1% at 100 mJy. Eight of the matched AT20G sources have no association listed in 1FGL and are presented here as potential gamma-ray AGNs for the first time. The authors also identify an alternative AGN counterpart to one 1FGL source. The percentage of Fermi sources with AT20G detections decreases toward the Galactic plane, suggesting that the 1FGL catalog contains at least 50 Galactic gamma-ray sources in the southern hemisphere that are yet to be identified. This table contains the complete list of all 233 Fermi-AT20G matches. This table was created by the HEASARC in August 2010 based on the electronic version of Table 4 obtained from the ApJ web site. This is a service provided by NASA HEASARC .
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Fermi 2FGL Unassociated Gamma-Ray Sources Possible Radio Identifications
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This table contains some of the results from an all-sky radio survey between 5- and 9-GHz of sky areas surrounding all unassociated gamma-ray objects listed in the Fermi Large Area Telescope (LAT) Second Source Catalog (2FGL). The goal of these observations is to find all new gamma-ray active galactic nucleus (AGN) associations with radio sources > 10 mJy at 8GHz. The authors observed with the Very Large Array (VLA) and the Australia Telescope Compact Array (ATCA) the areas around unassociated sources, providing localizations of weak radio point sources found in 2FGL fields at arcminute scales. They then followed up a subset of these with the Very Long Baseline Array (VLBA) and the Long Baseline Array (LBA) in order to confirm detections of radio emission on parsec-scales. The authors quantified association probabilities based on known statistics of source counts and assuming a uniform distribution of background sources. In total, they found 865 radio sources at arcsecond scales as candidates for association and detected 95 of 170 selected for follow-up observations at milliarcsecond resolution. Based on this, they obtained firm associations for 76 previously unknown gamma-ray AGNs. Comparison of these new AGN associations with the predictions from using the Wide-field Infrared Survey Explorer (WISE) color-color diagram shows that half of the associations are missed. The authors found that in 129 out of 588 gamma-ray sources observed at arcminute scales not a single radio continuum source was detected above their sensitivity limit within the 3-sigma gamma-ray localization. These "empty" fields were found to be particularly concentrated at low Galactic latitudes. The nature of these Galactic gamma-ray emitters is not yet determined. A list of 216 target fields were observed with the VLA. The instantaneous bandwidth was split into two parts, with one half centered at 5.0 GHz (4.5 - 5.5 GHz) and the other centered at 7.3 GHz (6.8 - 7.8 GHz). The observations were made on 2012 October 26 and 2012 November 3. See section 2.1 of the reference paper for more details. These data are included in this HEASARC table. During the first campaign with the ATCA from 2012 September 19-20, the authors observed 411 2FGL unassociated sources in a Declination range of -90 degrees to +10 degrees at 5.5 and 9 GHz. The details of this observing campaign and results have been reported by Petrov et al. (2013, MNRAS, 432, 1294: available at the HEASARC as the AT2FGLUS table). The authors detected a total of 424 point sources. In a second ATCA campaign on 2013 September 25-28, the authors re-observed sources that were detected at 5 GHz, but were not detected at 9 GHz. See section 2.2 of the reference paper for more details. These data are included in this HEASARC table. Follow-up observations of 149 targets selected from the VLA and ATCA surveys above -30 degrees Declination were conducted with the VLBA between 2013 Feb-Aug (VCS7 project; 4.128 - 4.608 and 7.392 - 7.872 GHz simultaneously) and in 2013 Jun-Dec (campaign S5272; 7.392 - 7.872 GHz only). See section 2.3 of the reference paper for more details. These data are NOT included in this HEASARC table. For sources with Declination below -30 degrees, the authors added 21 objects to the on-going LCS campaign being conducted using the LBA (Petrov et al. 2011, MNRAS, 414, 2528) in 2013 Mar-2013 Jun at 8.200 - 8.520 GHz. See section 2.4 of the reference paper for more details. These data are NOT included in this HEASARC table. This table was created by the HEASARC in May 2015 based on the union of CDS Catalog J/ApJS/217/4/ files table2.dat (the 148 'Category I' objects that were detected at 5.0/5.5 and/or 7.3/9.0 GHz within 2.7' of the 2FGL counterpart localization), table3.dat (the 501 'Category II' objects that were detected at 5.0/5.5 and/or 7.3/9.0 GHz between 2.7' and 6.5' of the 2FGL counterpart localization) and table4.dat (the 216
Australia Telescope 2FGL Unassociated Sources Radio Source Catalog
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The authors report results of the first phase of observations with the Australia Telescope Compact Array (ATCA) at 5 and 9 GHz of the fields around 411 gamma-ray sources having declinations less than +10 degrees which were detected by the Fermi Gamma-ray Space Telescope, but marked as unassociated in the 2nd Fermi Large-Area Telescope (2FGL) Catalog (available at the HEASARC as the FERMILPSC table). They have detected 424 radio sources with flux densities in the range from 2 mJy to 6 Jy in the fields of 283 gamma-ray sources within their gamma-ray position error ellipses (drawn to cover the area of 99 per cent probability of their localization). Of these, 146 objects were detected in both 5- and 9-GHz bands. The authors found 84 sources with spectral indices flatter than -0.5 in their sample. The majority of detected sources are weaker than 100 mJy and for this reason were not found in previous surveys. Approximately 1/3 of this sample, 128 objects, have the probability of being associated which is more than 10 times the probability of their being a background source found in the vicinity of the gamma-ray object by chance. This table contains the catalog of positions of these radio sources, estimates of their flux densities and their spectral indices, when available. This table was created by the HEASARC in July 2013 based on the electronic versions of Tables 1, 2 and 3 from the reference paper which were obtained from the MNRAS web site. This is a service provided by NASA HEASARC .
Low-Frequency Radio Catalog of Flat-Spectrum Sources
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A well-known property of the gamma-ray sources detected by Cos-B in the 1970s, by the Compton Gamma-Ray Observatory in the 1990s, and recently by the Fermi Gamma-ray Observatory is the presence of radio counterparts, particularly for those associated with extragalactic objects. This observational evidence is the basis of the radio/gamma-ray connection established for the class of active galactic nuclei known as blazars. In particular, the main spectral property of the radio counterparts associated with gamma-ray blazars is that they show a flat spectrum in the GHz frequency range. The authors' recent analysis dedicated to search for blazar-like candidates as potential counterparts for the unidentified gamma-ray sources allowed them to extend the radio/gamma-ray connection in the MHz regime. They also showed that blazars below 1 GHz maintain flat radio spectra. Thus, on the basis of these new results, the authors have assembled a low-frequency radio catalog of flat-spectrum sources built by combining the radio observations of the Westerbork Northern Sky Survey (WENSS) and of the Westerbork in the southern hemisphere (WISH) catalogs with those of the NRAO Very Large Array Sky survey (NVSS). This catalog could be used in the future to search for new, unknown blazar-like counterparts of gamma-ray sources. First, the authors found NVSS counterparts of Westerbork Synthesis Radio Telescope (WSRT) radio sources, and then they selected flat-spectrum radio sources according to a new spectral criterion, specifically defined for radio observations performed below 1 GHz. In their paper, they also describe the main properties of the catalog listing 28,358 radio sources with spectral indices between 1400 and 325/352 MHz between -1.0 and +0.4, and their log N - log S distributions. Finally, a comparison with the Green Bank 6 cm radio source catalog was performed so as to investigate the spectral shape of the low-frequency flat-spectrum radio sources at higher frequencies. This table was created by the HEASARC in July 2014 based on a 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 .
Extragalactic Radio Sources
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This catalog is a compilation of 518 extragalactic radio sources with flux densities greater than 1 Jy at 5 GHz. It contains sources from the NRAO-MPI 5-GHz Strong Source Surveys and from re-observation at 5 GHz of sources found in the Parkes 2.7-GHz surveys. All sources were found in 9.811 sr covered by the two surveys. This is essentially the whole sky, excluding the galactic plane (latitudes less than 10 degrees) and the Magellanic Clouds. The catalog includes radio flux densities, radio positions, object classes, visual magnitudes, redshifts, and spectral indices. One duplicate entry was removed from the HEASARC implementation of this catalog in June 2019. This is a service provided by NASA HEASARC .
COSMOS Field VLBA Observations 1.4-GHz Source Catalog
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This table contains the results of a project using wide-field Very Long Baseline Interferometry (VLBI) observations at 1.4 GHz of 2,865 known radio sources in the Cosmic Evolution Survey (COSMOS) field, a field which has exceptional multi-wavelength coverage. The main objective of this study is to identify the active galactic nuclei (AGN) in this field. Wide-field VLBI observations were made of all known radio sources in the COSMOS field at 1.4 GHz using the Very Long Baseline Array (VLBA). The authors also collected complementary multiwavelength information from the literature for the VLBA-detected sources.The combination of the number of sources, sensitivity, angular resolution and the area covered by this project are unprecedented. A catalog which contains the VLBI-detected sources is presented, the main purpose of which is to be used as an AGN catalog. the complementary multiwavelength (optical, infrared and X-ray) information of the VLBI-detected sources is also presented. The authors have detected 468 radio sources, expected to be AGN, with the VLBA. This is, to date, the largest sample assembled of VLBI-detected sources in the sub-mJy regime. They find a detection fraction of 20% +/- 1%, considering only those sources from the input catalog which were in principle detectable with the VLBA (2,361). As a function of the VLA flux density, the detection fraction is higher for higher flux densities, since at high flux densities a source could be detected even if the VLBI core accounts for a small percentage of the total flux density. As a function of redshift, the authors see no evolution of the detection fraction over the redshift range 0.5 < z < 3. In addition, they find that faint radio sources typically have a greater fraction of their radio luminosity in a compact core: ~70% of the sub-mJy sources detected with the VLBA have more than half of their total radio luminosity in a VLBI-scale component, whereas this is true for only ~30% of the sources that are brighter than 10 mJy. This suggests that fainter radio sources differ intrinsically from brighter ones. Across the entire sample, the authors find the predominant morphological classification of the host galaxies of the VLBA-detected sources to be early type (57%), although this varies with redshift and at z > 1.5 they find that spiral galaxies become the most prevalent (48%). The number of detections is high enough to study the faint radio population with statistically significant numbers. The authors demonstrate that wide-field VLBI observations, together with new calibration methods such as multi-source self-calibration and mosaicking, result in information which is difficult or impossible to obtain otherwise. This table contains 504 entries, including the 468 VLBA-detected sources and, for sources with multiple components, entries for the individual components. Among the detected sources, there are 452 single, 13 double, 2 triple and 1 quadruple source. Source entries have no suffix in their vlba_source_id, e.g., 'C3293', whereas component entries have a, b, c or d suffixes, e.g., 'C0090a' (and a value of 2 for the multi_cpt_flag parameter). This table was created by the HEASARC in December 2017 based on CDS Catalog J/A+A/607/A132 files vlba_cat.dat and vlba_mw.dat. This is a service provided by NASA HEASARC .
CRATES Flat-Spectrum Radio Source Catalog
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The authors have assembled an 8.4 GHz survey of bright, flat-spectrum (alpha > -0.5) radio sources with nearly uniform extragalactic (|b| > 10 degrees) coverage for sources brighter than a 4.8 GHz flux density S_4.8GHz = 65 mJy. The catalog is assembled from existing observations (especially the Cosmic Lens All-Sky Survey, CLASS, and the Wright et al. PMN-CA survey), augmented by reprocessing of archival VLA and ATCA data and by new observations to fill in coverage gaps. The authors refer to this program as CRATES, the Combined Radio All-Sky Targeted Eight-GHz Survey. The resulting catalog provides precise positions, subarcsecond structures, and spectral indices for some 11,000 sources. The authors describe the morphology and spectral index distribution of the sample and comment on the survey's power to select several classes of interesting sources, especially high-energy blazars. Comparison of CRATES with other high-frequency surveys also provides unique opportunities for identification of high-power radio sources. This table contains 14467 entries, where each entry corresponds to an 8.4-GHz counterpart source (or absence thereof) to one of 11,131 4.8-GHz sources. The number of entries exceeds the number of 4.8-GHz sources because there are many cases in which there are multiple (from 2 - 20) 8.4-GHz counterparts to a single 4.8-GHz source. There are also 762 entries in which no 8.4-GHz counterpart was detected (morph_type = 'N'). This table was created by the HEASARC in August 2007 based on the electronic version of Table 5 obtained from the electronic ApJ web site. This is a service provided by NASA HEASARC .
Owens Valley Radio Observatory 40-m 31-GHZ Radio Source Catalog
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The 100m Robert C. Byrd Green Bank Telescope (GBT) and the 40m Owens Valley Radio Observatory (OVRO) telescope have been used to conduct a 31-GHz survey of 3165 known extragalactic radio sources over 143 deg2 of the sky. Target sources were selected from the NRAO VLA Sky Survey (NVSS) in fields observed by the Cosmic Background Imager (CBI); most are extragalactic active galactic nuclei (AGNs) with 1.4-GHz flux densities of 3-10 mJy. Using a maximum-likelihood analysis to obtain an unbiased estimate of the distribution of the 1.4 - 31 GHz spectral indices of these sources, the authors find a mean 31 - 1.4 GHz flux ratio of 0.110 +/- 0.003 corresponding to a spectral index alpha = -0.71+/-0.01 (Snu ~ nualpha); 9.0% +/- 0.8% of the sources have alpha > -0.5 and 1.2% +/- 0.2% have alpha > 0. By combining this spectral-index distribution with 1.4GHz source counts, the authors predict 31-GHz source counts in the range 1 mJy 31 < 4 mJy, N(>S31) = (16.7+/-1.7)deg-2(S31/1mJy)(-0.80+/-0.07). In this study, the authors present a detailed characterization of the impact of the discrete source foreground on arcminute-scale 31-GHz anisotropy measurements based upon two observational campaigns. The first campaign (the results of which are given in this table) was carried out with the OVRO 40m telescope at 31 GHz from 2000 September through 2002 December. The second campaign (the results of which are given in the GBT31GHZ table) used the GBT from 2006 February to May. A companion paper (Sievers et al. 2009arXiv0901.4540S) presents the five-year CBI total intensity power spectrum incorporating the results of the point-source measurements discussed here. Reported error bars include a 10% and 5% rms gain uncertainty for GBT and OVRO measurements, respectively. Sources detected at greater than 4 sigma at 31 GHz are flagged (detection_flag = 'Y'); for this calculation, the random gain uncertainty was excluded. In all 3165 sources were observed. The GBT catalog (the HEASARC GBT31GHZ table) contains 1490 sources. Of the 2315 useful OVRO observations many of the non-detections (and a few detections) were superceded by more sensitive GBT observations; the OVRO catalog contained in the present table therefore contains data on 1675 sources. The detection rate of the OVRO measurements was 11%, and that of the GBT measurements 25%. In all, 18% of the sources were detected at 31 GHz. This table was created by the HEASARC in June 2012 based on CDS Catalpog J/ApJ/704/1433 file table2.dat. This is a service provided by NASA HEASARC .
Fermi LAT High-Energy Source Catalog (1FHL)
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This table contains the catalog of gamma-ray sources at energies above 10 GeV based on data from the Large Area Telescope (LAT) accumulated during the first 3 years of the Fermi Gamma-ray Space Telescope mission. The first Fermi-LAT catalog of > 10 GeV sources (1FHL) has 514 sources. For each source, the authors present location, spectrum, a measure of variability,and associations with cataloged sources at other wavelengths. They found that 449 (87%) could be associated with known sources, of which 393 (76% of the 1FHL sources) are active galactic nuclei. Of the 27 sources associated with known pulsars, they find 20 (12) to have significant pulsations in the range > 10 GeV (> 25 GeV). In this work, the authors also report that, at energies above 10 GeV, unresolved sources account for 27% +/- 8% of the isotropic gamma-ray background, while the unresolved Galactic population contributes only at the few percent level to the Galactic diffuse background. The authors also highlight the subset of the 1FHL sources that are the best candidates for detection at energies above 50 - 100 GeV with current and future ground-based gamma-ray observatories. The time interval analyzed here is from the beginning of Fermi LAT science operations on 2008 August 4 (MET 239557447) to 2011 August 1 (MET 333849586), covering very nearly 3 years. In this work, the authors analyze gamma rays with energies in the range 10-500 GeV. To limit the contamination from gamma rays produced by cosmic-ray interactions in the upper atmosphere, gamma rays with zenith angles greater than 105 degrees were excluded. To further reduce the residual gamma rays from the upper atmosphere only data for time periods when the spacecraft rocking angle was less than 52 degrees were considered. See Section 2 of the reference paper for further explanations. This table was created by the HEASARC in April 2015 based on CDS Catalog J/ApJS/209/34/ files table3.dat and table7.dat. This is a service provided by NASA HEASARC .
Green Bank Telescope 100-m 31-GHZ Radio Source Catalog
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The 100m Robert C. Byrd Green Bank Telescope (GBT) and the 40m Owens Valley Radio Observatory (OVRO) telescope have been used to conduct a 31-GHz survey of 3165 known extragalactic radio sources over 143 deg2 of the sky. Target sources were selected from the NRAO VLA Sky Survey (NVSS) in fields observed by the Cosmic Background Imager (CBI); most are extragalactic active galactic nuclei (AGNs) with 1.4-GHz flux densities of 3-10 mJy. Using a maximum-likelihood analysis to obtain an unbiased estimate of the distribution of the 1.4 - 31 GHz spectral indices of these sources, the authors find a mean 31 - 1.4 GHz flux ratio of 0.110 +/- 0.003 corresponding to a spectral index alpha = -0.71+/-0.01 (Snu ~ nualpha); 9.0% +/- 0.8% of the sources have alpha > -0.5 and 1.2% +/- 0.2% have alpha > 0. By combining this spectral-index distribution with 1.4GHz source counts, the authors predict 31-GHz source counts in the range 1 mJy 31 < 4 mJy, N(>S31) = (16.7+/-1.7)deg-2(S31/1mJy)(-0.80+/-0.07). In this study, the authors present a detailed characterization of the impact of the discrete source foreground on arcminute-scale 31-GHz anisotropy measurements based upon two observational campaigns. The first campaign (the results of which are given in the OVRO31GHZ table) was carried out with the OVRO 40m telescope at 31 GHz from 2000 September through 2002 December. The second campaign (the results of which are given in the present table) used the GBT from 2006 February to May. A companion paper (Sievers et al. 2009arXiv0901.4540S) presents the five-year CBI total intensity power spectrum incorporating the results of the point-source measurements discussed here. Reported error bars include a 10% and 5% rms gain uncertainty for GBT and OVRO measurements, respectively. Sources detected at greater than 4 sigma at 31 GHz are flagged (detection_flag = 'Y'); for this calculation, the random gain uncertainty was excluded. In all 3165 sources were observed. The GBT catalog (this table) contains 1490 sources. Of the 2315 useful OVRO observations many of the non-detections (and a few detections) were superceded by more sensitive GBT observations; the OVRO catalog contained in the HEASARC's OVRO31GHZ table therefore contains data on 1675 sources. The detection rate of the OVRO measurements was 11%, and that of the GBT measurements 25%. In all, 18% of the sources were detected at 31 GHz. This table was created by the HEASARC in June 2012 based on CDS Catalpog J/ApJ/704/1433 file table3.dat. This is a service provided by NASA HEASARC .
Atacama Cosmology Telescope 2008 Survey 148-GHz Extragalactic Source Catalog
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This table contains a list of extragalactic radio sources detected in a 455 square-degree map of the southern sky made at a frequency of 148 GHz from the Atacama Cosmology Telescope (ACT) 2008 observing season. This catalog has 157 sources with flux densities spanning two orders of magnitude from 15 to 1500 mJy. Comparison to other catalogs shows that 98% of the ACT detections correspond to sources detected at lower radio frequencies. Three of the sources appear to be associated with the brightest cluster galaxies of low redshift X-ray selected galaxy clusters. Estimates of the radio to mm-wave spectral indices and differential counts of the sources further bolster the hypothesis that they are nearly all radio sources, and that their emission is not dominated by re-emission from warm dust. In a bright (>50 mJy) 148 GHz-selected sample with complete cross-identifications from the Australia Telescope 20-GHz survey, the authors of the study observe an average steepening of the spectra between 5, 20, and 148 GHz with median spectral indices of alpha5-20 = -0.07 +/- 0.06, alpha20-148 = -0.39 +/- 0.04, and alpha5-148 = -0.20 +/- 0.03. When the measured spectral indices are taken into account, the 148-GHz differential source counts are consistent with previous measurements at 30 GHz in the context of a source count model dominated by flat spectrum radio sources. Extrapolating with an appropriately rescaled model for the radio source counts, the Poisson contribution to the spatial power spectrum from synchrotron-dominated sources with flux density less than 20 mJy is CSync = (2.8 +/- 0.3) x 10-6 microKelvin2. This table was created by the HEASARC in January 2011 based on an electronic version of Table A1 from the paper (the Point Source Catalog) which was obtained from the LAMBDA website at http://lambda.gsfc.nasa.gov/product/suborbit/act_prod_table.cfm This is a service provided by NASA HEASARC .