- ID:
- ivo://CDS.VizieR/J/ApJ/718/587
- Title:
- The Fermi-AT20G catalog
- Short Name:
- J/ApJ/718/587
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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, we have cross-matched the Australia Telescope 20 GHz survey catalog (AT20G) with the Fermi-LAT 1 year Point Source Catalog (1FGL). The 6.0sr of sky covered by both catalogs (DEC<0{deg},|b|>1.5{deg}) 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. We find a trend of increasing gamma-ray flux density with 20GHz radio flux density. The Fermi detection rate of AT20G sources is close to 100% for the brightest 20GHz sources, decreasing to 20% at 1Jy, and to roughly 1% at 100mJy. 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. We 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.
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- ID:
- ivo://CDS.VizieR/J/AJ/128/1646
- Title:
- The Galactic Center region at 330MHz
- Short Name:
- J/AJ/128/1646
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a wide-field, subarcminute-resolution VLA image of the Galactic center region at 330MHz. With a resolution of ~7"x12" and an rms noise of 1.6mJy/beam, this image represents a significant increase in resolution and sensitivity over the previously published VLA image at this frequency. The improved sensitivity has more than tripled the census of small-diameter sources in the region, has resulted in the detection of two new nonthermal filaments (NTFs), 18 NTF candidates, and 30 pulsar candidates, reveals previously known extended sources in greater detail, and has resulted in the first detection of Sagittarius A* in this frequency range.
- ID:
- ivo://CDS.VizieR/J/A+A/556/A1
- Title:
- The 2.3GHz continuum survey of the GEM project
- Short Name:
- J/A+A/556/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Determining the spectral and spatial characteristics of the radio continuum of our Galaxy is an experimentally challenging endeavour for improving our understanding of the astrophysics of the interstellar medium. This knowledge has also become of paramount significance for cosmology, since Galactic emission is the main source of astrophysical contamination in measurements of the Cosmic Microwave Background radiation. In this paper we present the scope of the Galactic Emission Mapping (GEM) project and its results at 2.3GHz. Its observational program was conceived and developed to reveal the large scale properties of Galactic synchrotron radiation in total intensity and polarisation through a self-consistent set of radio continuum surveys between 408MHz and 10GHz. GEM's unique observational strategy and experimental design aim at the production of foreground templates in order to address the mutual inconsistencies between existing surveys.
- ID:
- ivo://CDS.VizieR/J/A+A/598/A78
- Title:
- The GMRT 150MHz all-sky radio survey
- Short Name:
- J/A+A/598/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first full release of a survey of the 150MHz radio sky, observed with the Giant Metrewave Radio Telescope (GMRT) between April 2010 and March 2012 as part of the TIFR GMRT Sky Survey (TGSS) project. Aimed at producing a reliable compact source survey, our automated data reduction pipeline efficiently processed more than 2000h of observations with minimal human interaction. Through application of innovative techniques such as image-based flagging, direction-dependent calibration of ionospheric phase errors, correcting for systematic offsets in antenna pointing, and improving the primary beam model, we created good quality images for over 95 percent of the 5336 pointings. Our data release covers 36900deg^2^ (or 3.6{pi}steradians) of the sky between -53{deg} and +90{deg} declination (Dec), which is 90 percent of the total sky. The majority of pointing images have a noise level below 5mJy/beam with an approximate resolution of 25"x25" (or 25"x25"/cos(Dec-19{deg}) for pointings south of 19{deg} declination). We have produced a catalog of 0.62 Million radio sources derived from an initial, high reliability source extraction at the seven sigma level. For the bulk of the survey, the measured overall astrometric accuracy is better than two arcseconds in right ascension and declination, while the flux density accuracy is estimated at approximately ten percent. Within the scope of the TGSS alternative data release (TGSS ADR) project, the source catalog, as well as 5336 mosaic images (5{deg}x5{deg}) and an image cutout service, are made publicly available at the CDS as a service to the astronomical community. Next to enabling a wide range of different scientific investigations, we anticipate that these survey products will provide a solid reference for various new low-frequency radio aperture array telescopes (LOFAR, LWA, MWA, SKA-low), and can play an important role in characterizing the epoch-of-reionisation (EoR) foreground. The TGSS ADR project aims at continuously improving the quality of the survey data products. Near-future improvements include replacement of bright source snapshot images with archival targeted observations, using new observations to fill the holes in sky coverage and replace very poor quality observational data, and an improved flux calibration strategy for less severely affected observational data.
- ID:
- ivo://CDS.VizieR/VIII/53
- Title:
- The Green Bank Survey
- Short Name:
- VIII/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog presents the parts I, II, and III of the Green Bank survey of extragalactic radio sources at 1400 MHz. The data were obtained with the 300' antenna, producing a beamwidth of 10'x11' FWHM. Part I of the survey covers about 521 square degrees of the sky with RA from 7h17m to 16h23m, DEC from +45.8{deg} to +51.7{deg}. 1086 sources are presented down to a limiting flux density of 90 mJy. These data were originally published in Maslowski, 1972, Acta Astronomica, 22, 227 (1972AcA....22..227M). Part II of the survey covers 0.28 sr of the sky with RA from 7h08m to 16h57m, DEC from +31.9{deg} to +39.7{deg}. 2022 sources are presented down to a limiting flux density of 0.09 mJy. Spectral indices between 1400 MHz and 408 MHz are determined for most sources by comparison with the B2 source catalog (Cat.<VIII/36>). These data were originally published in Machalski 1978, Acta Astronomica, 28, 367 (1978AcA....28..367M) Part III of the survey covers an area of 0.099 sr at declinations between 70 and 76.8 degrees. This catalog contains a total of 676 radio sources, of which 502 are statistically complete to 112 mJy. These data were originally published as Rys and Machalski, 1987, Acta Astronomica, 37, 163 (1987AcA....37..163R).
- ID:
- ivo://CDS.VizieR/J/ApJ/844/78
- Title:
- The high-redshift COBRA survey: IRAC obs.
- Short Name:
- J/ApJ/844/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 190 galaxy cluster candidates (most at high redshift) based on galaxy overdensity measurements in the Spitzer/IRAC imaging of the fields surrounding 646 bent, double-lobed radio sources drawn from the Clusters Occupied by Bent Radio AGN (COBRA) Survey. The COBRA sources were chosen as objects in the Very Large Array FIRST survey that lack optical counterparts in the Sloan Digital Sky Survey to a limit of m_r_=22, making them likely to lie at high redshift. This is confirmed by our observations: the redshift distribution of COBRA sources with estimated redshifts peaks near z=1 and extends out to z~3. Cluster candidates were identified by comparing our target fields to a background field and searching for statistically significant (>=2{sigma}) excesses in the galaxy number counts surrounding the radio sources; 190 fields satisfy the >=2{sigma} limit. We find that 530 fields (82.0%) have a net positive excess of galaxies surrounding the radio source. Many of the fields with positive excesses but below the 2{sigma} cutoff are likely to be galaxy groups. Forty-one COBRA sources are quasars with known spectroscopic redshifts, which may be tracers of some of the most distant clusters known.
- ID:
- ivo://CDS.VizieR/VIII/52B
- Title:
- The MIT-Green Bank 5GHz Survey
- Short Name:
- VIII/52B
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The MIT-Green Bank 5GHz survey catalog was produced from four separate surveys with the National Radio Astronomy Observatory (NRAO) 91m transit telescope (Bennett et al., 1986ApJS...61....1B (MG1); Langston et al., 1990ApJS...72..621L (MG2); Griffith et al., 1990ApJS...74..129G (MG3); Griffith et al. 1991ApJS...75..801G (MG4)). The sky coverage of the various surveys is: 00h < RAB < 24h, -00d30'13" < DECB < +19d29'47" for MG1; 04h < RAJ < 21h, +17.0d < DECJ < +39d09' for MG2; 16h30m < RAB < 05h, +17d < DECB < +39d09' for MG3; and 15h30m < RAB < 02h30m, +37.00d < DECB < +50d58'48" for MG4; where RAB and DECB refer to B1950 coordinates, and RAJ and DECJ refer to J2000 coordinates. The catalog contains 20344 sources detected with a signal-to-noise ratio greater than 5 and 3836 possible detections (MG1) with a signal-to-noise ratio less than 5. Spectral indices are computed for MG1 sources also identified in the Texas 365MHz survey (Douglas et al. 1980), and for MG1-MG4 sources also identified in the NRAO 1400MHz Survey (Condon and Broderick 1985).
- ID:
- ivo://CDS.VizieR/J/A+AS/99/545
- Title:
- The Miyun 232 MHz survey. I
- Short Name:
- J/A+AS/99/545
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains a new meter-wave survey of the sky region north of declination 30{deg}, carried out with the Miyun 232 MHz SSSynthesis Radio Telescope (MSRT) at HPBW 3.8' x 3.8' cosec(dec). Results from two fields are presented here; the fields are 8 degrees on a side, centered at 0041+41.2 and 0700+35.0. The accuracy of flux determination is limited by background fluctuation which is about 30 mJy. The catalogue is complete for sources with flux greater than 0.25 Jy. The total number of sources listed in the catalogue is 687.
- ID:
- ivo://CDS.VizieR/J/AJ/131/100
- Title:
- The Molonglo Southern 4Jy sample. I
- Short Name:
- J/AJ/131/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have defined a complete sample of 228 southern radio sources at 408MHz with integrated flux densities S(408)>4.0Jy, Galactic latitude |b|>10{deg}, and declination -85{deg}<{delta}<-30{deg}. The main finding survey used was the Molonglo Reference Catalogue (Cat. <VIII/16>). Sources in the sample were imaged at 843MHz with the Molonglo Observatory Synthesis Telescope to obtain positions accurate to about 1", as well as flux densities and angular sizes.
- ID:
- ivo://CDS.VizieR/J/AJ/131/114
- Title:
- The Molonglo Southern 4Jy sample. II
- Short Name:
- J/AJ/131/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Of the 228 sources in the Molonglo Southern 4Jy sample (MS4, Cat. J/AJ/131/100), the 133 with angular sizes <35" have been imaged at 5GHz at 2"-4" resolution with the Australia Telescope Compact Array. More than 90% of the sample has been reliably optically identified, either on the plates of the UK Schmidt Southern Sky Survey or on R-band CCD images made with the Anglo-Australian Telescope.