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- ID:
- ivo://CDS.VizieR/J/ApJ/559/864
- Title:
- Extragalactic ultracompact H II regions
- Short Name:
- J/ApJ/559/864
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the detection of optically thick free-free radio sources in the galaxies M33, NGC 253, and NGC 6946 using data in the literature. We interpret these sources as being young embedded star birth regions that are likely to be clusters of ultracompact H II regions. All 35 of the sources presented in this article have positive radio spectral indices ({alpha}>0 for S_{nu}_){prop.to}{nu}^{alpha}^), suggesting an optically thick thermal bremsstrahlung origin from the H II region surrounding the hot stars.
- ID:
- ivo://CDS.VizieR/J/A+AS/132/305
- Title:
- Extragal. radio sources at 22, 37 and 87GHz
- Short Name:
- J/A+AS/132/305
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Over 13500 continuum observations of extragalactic sources are presented. These observations of 157 sources at 22, 37 and 87GHz more than doubles the millimeter observations of these sources. The data are between 1990.5 and 1995.5, and combined with our earlier published data form a 15 year database.
- ID:
- ivo://CDS.VizieR/J/ApJS/45/97
- Title:
- Extragal. Radio Sources Faraday Rotation
- Short Name:
- J/ApJS/45/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The rotation measures of 555 extragalactic radio sources are calculated as a result of a large number of new linear polarization measurements carried out by us at several wavelengths between 1.59 and 10.5GHz. A summary of references for previous polarization measurements is included, and the procedure for optimizing the number of unambiguous rotation measures is described.
- ID:
- ivo://CDS.VizieR/J/A+A/402/171
- Title:
- Faint CSS radio sources at 74 MHz
- Short Name:
- J/A+A/402/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out VLA observations in A configuration at 74-MHz of a new sample of faint Compact Steep-Spectrum (CSS) radio sources as part of a comprehensive project to study the nature and evolution of peaked-spectrum radio sources. In conjunction with higher frequency spectral information this has enabled us to determine the peak frequency and peak flux density of the spectral turnover for 35 faint CSS radio sources. Spectra are presented. An analysis is given of the quality of the images and their suitability for integrated intensity measurements of the CSS radio sources.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2565
- Title:
- Faint FIRST variable radio sources
- Short Name:
- J/AJ/127/2565
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 123 radio sources that exhibit significant variations at 1.4GHz on a 7 year baseline has been created using FIRST VLA B-configuration data from 1995 and 2002 on a strip at {delta}=0 near the south Galactic cap. This sample spans the range of radio flux densities from ~2 to 1000mJy. It presents both in size and radio flux density range a unique starting point for variability studies of galaxies and quasars harboring lower luminosity active galactic nuclei (AGNs).
- ID:
- ivo://CDS.VizieR/J/MNRAS/352/1245
- Title:
- Faint 1.4GHz radio sources in 2dFGRS
- Short Name:
- J/MNRAS/352/1245
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Australia Telescope Compact Array (ATCA) to search for faint radio sources in a ~3deg^2^ region of sky covered by the 2dF Galaxy Redshift Survey (2dFGRS, Cat. <VII/226>). Over the region surveyed, the 1{sigma} noise level at 1.4GHz ranges from 20Jy to 1mJy. The survey region includes 365 2dFGRS galaxies, of which 316 have good-quality spectra (176 early-type galaxies or active galactic nuclei, and 140 star-forming galaxies). The fraction of 2dFGRS galaxies detected as radio sources in our survey rises from ~4% at a 3{sigma} detection limit of 0.3mJy to 12% at 75{mu}Jy, with roughly equal numbers of star-forming galaxies and active galactic nuclei (AGNs) being detected.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/4244
- Title:
- Faint radio source population at 15.7GHz
- Short Name:
- J/MNRAS/453/4244
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A complete, flux density limited sample of 96 faint (>0.5mJy) radio sources is selected from the 10C survey at 15.7GHz in the Lockman Hole. We have matched this sample to a range of multi-wavelength catalogues, including Spitzer Extragalactic Representative Volume Survey, Spitzer Wide-area Infrared Extragalactic survey, United Kingdom Infrared Telescope Infrared Deep Sky Survey and optical data; multi-wavelength counterparts are found for 80 of the 96 sources and spectroscopic redshifts are available for 24 sources. Photometric redshifts are estimated for the sources with multi-wavelength data available; the median redshift of the sample is 0.91 with an interquartile range of 0.84. Radio-to-optical ratios show that at least 94 per cent of the sample are radio loud, indicating that the 10C sample is dominated by radio galaxies. This is in contrast to samples selected at lower frequencies, where radio-quiet AGN and star-forming galaxies are present in significant numbers at these flux density levels. All six radio-quiet sources have rising radio spectra, suggesting that they are dominated by AGN emission. These results confirm the conclusions of that the faint, flat-spectrum sources which are found to dominate the 10C sample below ~1mJy are the cores of radio galaxies. The properties of the 10C sample are compared to the Square Kilometre Array Design Studies Simulated Skies; a population of low-redshift star-forming galaxies predicted by the simulation is not found in the observed sample.
- ID:
- ivo://CDS.VizieR/J/ApJ/875/80
- Title:
- Faint radio sources in GOODS-N and -S. I. VLA 5GHz
- Short Name:
- J/ApJ/875/80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from the deep and wide 5GHz radio observations of the Great Observatories Origins Deep Survey (GOODS)-North ({sigma}=3.5{mu}Jy/beam, synthesized beam size {theta}=1.47"x1.42", and 52 sources over 109arcmin^2^) and GOODS-South ({sigma}=3.0{mu}Jy/beam, {theta}=0.98"x0.45", and 88 sources over 190arcmin^2^) fields using the Karl G. Jansky Very Large Array. We derive radio spectral indices {alpha} between 1.4 and 5GHz using the beam-matched images and show that the overall spectral index distribution is broad even when the measured noise and flux bias are considered. We also find a clustering of faint radio sources around {alpha}=0.8, but only within S_5GHz_<150{mu}Jy. We demonstrate that the correct radio spectral index is important for deriving accurate rest-frame radio power and analyzing the radio-FIR correlation, and adopting a single value of {alpha}=0.8 leads to a significant scatter and a strong bias in the analysis of the radio-FIR correlation, resulting from the broad and asymmetric spectral index distribution. When characterized by specific star formation rates, the starburst population (58%) dominates the 5GHz radio source population, and the quiescent galaxy population (30%) follows a distinct trend in spectral index distribution and the radio-FIR correlation. Lastly, we offer suggestions on sensitivity and angular resolution for future ultra-deep surveys designed to trace the cosmic history of star formation and AGN activity using radio continuum as a probe.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1216
- Title:
- Faint radio sources in the CDF-S ACS field
- Short Name:
- J/AJ/131/1216
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and X-ray identifications for the 64 radio sources in the Great Observatories Origins Deep Survey (GOODS) in Chandra Deep Field-South Advanced Camera for Surveys (ACS) field revealed in the Australia Telescope Compact Array 1.4GHz survey of the Chandra Deep Field-South. Optical identifications are made using the ACS images and catalogs, while the X-ray view is provided by the Chandra X-Ray Observatory 1Ms observations. Redshifts for the identified sources are drawn from publicly available catalogs of spectroscopic observations and multiband photometric-based estimates. Using this multiwavelength information we provide a first characterization of the faint radio source population in this region.
