- ID:
- ivo://CDS.VizieR/VIII/9
- Title:
- Argentina High-Latitude H I Survey
- Short Name:
- VIII/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This survey consists of H I 21-cm spectra covering the southern sky with absolute galactic latitude |b|>10 degrees and a declination dec<-25 degrees. The observations were made with the 30m telescope of the Instituto Argentino de Radioastronomia during 1973 to 1977 and were described in Colomb et al. (1977A&AS...29...89C). The data were obtained by keeping the telescope fixed on the meridian at the desired declination and letting the sky drift through the field. The individual spectra were obtained with a 56-channel filterbank and covering the velocity range from about -40 to +40km/s. The velocity resolution is 2km/s, and the beamwidth is 30arcmin.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/490/1202
- Title:
- ASKAP EMU ESP, Radio Continuum Survey of the SMC
- Short Name:
- J/MNRAS/490/1202
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present two new radio continuum images from the Australian Square Kilometre Array Pathnder (ASKAP) survey in the direction of the Small Magellanic Cloud (SMC). These images are part of the Evolutionary Map of the Universe (EMU) Early Science Project (ESP) survey of the Small and Large Magellanic Clouds. The two new source lists produced from these images contain radio continuum sources observed at 960MHz (4489 sources) and 1320MHz (5954 sources) with a bandwidth of 192MHz and beam sizes of 30.0"x30.0" and 16.3"x15.1", respectively. The median Root Mean Squared (RMS) noise values are 186Jy/beam (960MHz) and 165Jy/beam (1320MHz). To create point source catalogues, we use these two source lists, together with the previously published Molonglo Observatory Synthesis Telescope (MOST) and the Australia Telescope Compact Array (ATCA) point source catalogues to estimate spectral indices for the whole population of radio point sources found in the survey region. Combining our ASKAP catalogues with these radio continuum surveys, we found 7736 point-like sources in common over an area of 30deg^2^. In addition, we report the detection of two new, low surface brightness supernova remnant candidates in the SMC. The high sensitivity of the new ASKAP ESP survey also enabled us to detect the bright end of the SMC planetary nebula sample, with 22 out of 102 optically known planetary nebulae showing point-like radio continuum emission. Lastly, we present several morphologically interesting background radio galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/753/83
- Title:
- Associations to 1FGL sources
- Short Name:
- J/ApJ/753/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Fermi Large Area Telescope (LAT) First Source Catalog (1FGL) provided spatial, spectral, and temporal properties for a large number of {gamma}-ray sources using a uniform analysis method. After correlating with the most-complete catalogs of source types known to emit {gamma} rays, 630 of these sources are "unassociated" (i.e., have no obvious counterparts at other wavelengths). Here, we employ two statistical analyses of the primary {gamma}-ray characteristics for these unassociated sources in an effort to correlate their {gamma}-ray properties with the active galactic nucleus (AGN) and pulsar populations in 1FGL. Based on the correlation results, we classify 221 AGN-like and 134 pulsar-like sources in the 1FGL unassociated sources. The results of these source "classifications" appear to match the expected source distributions, especially at high Galactic latitudes. While useful for planning future multiwavelength follow-up observations, these analyses use limited inputs, and their predictions should not be considered equivalent to "probable source classes" for these sources. We discuss multiwavelength results and catalog cross-correlations to date, and provide new source associations for 229 Fermi-LAT sources that had no association listed in the 1FGL catalog. By validating the source classifications against these new associations, we find that the new association matches the predicted source class in ~80% of the sources.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A80
- Title:
- Astrometric classification of 647 VLBI sources
- Short Name:
- J/A+A/618/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the result of our Allan standard deviation based classification according to their astrometric stability. The classification is divided into three categories (stable sources, intermediate sources, unstable sources). Stability of sources is qualified by the astrometric behavior of the source. This determines in which category the source falls into. Then, stability of the source is also quantified by a stability index (two are proposed in the table). Those indexes enable to order sources in each category of the classification.
- ID:
- ivo://CDS.VizieR/J/A+A/510/A10
- Title:
- Astrometric positions of radio sources
- Short Name:
- J/A+A/510/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss the results of an investigation of astrometric positions of extragalactic radio sources from a list for the International Celestial Reference Frame.
- ID:
- ivo://CDS.VizieR/VIII/58
- Title:
- A Survey of Radio H II Regions in the Northern Sky
- Short Name:
- VIII/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Nearly 500 radio continuum sources near the Galactic plane at declinations greater than -37 degrees were examined for radio recombination line emission to see if they might be HII regions. A total of 462 were detected, about half of these for the first time. The data are presented in an extensive table. Among the newly discovered nebulae are several with recombinations lines so narrow that their electron temperature must be less than 4600 K. In one case the line width (in several transitions) is only 11.6 km/s, requiring electron temperatures less than about 2900 K.
- ID:
- ivo://CDS.VizieR/J/A+A/281/15
- Title:
- Asymmetries in radio source structures
- Short Name:
- J/A+A/281/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/MNRAS/354/305
- Title:
- ATCA 18GHz pilot survey first results
- Short Name:
- J/MNRAS/354/305
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a pilot study for the first all-sky radio survey at short wavelengths, we have observed 1216deg^2^ of the southern sky at 18GHz (16mm) using a novel wide-band (3.4-GHz bandwidth) analogue correlator on one baseline of the Australia Telescope Compact Array. We scanned a region of sky between declination -71{deg} and -59{deg} with an rms noise level of 15mJy. Follow-up radio imaging of candidate sources above a 4{sigma} detection limit of 60mJy resulted in 221 confirmed detections, for which we have measured accurate positions and flux densities. For extragalactic sources, the survey is roughly 70 per cent complete at a flux density of 126mJy and 95 per cent complete above 300mJy. Almost half the detected sources lie within a few degrees of the Galactic plane, but there are 123 sources with |b|>5{deg}, which can be assumed to be extragalactic.
- ID:
- ivo://CDS.VizieR/J/MNRAS/325/1411
- Title:
- ATCA Intraday Variability Survey
- Short Name:
- J/MNRAS/325/1411
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an Australia Telescope Compact Array (ATCA) survey for intraday variability (IDV) of the total and polarized flux densities of 118 compact, flat-spectrum, extragalactic radio sources from the Parkes 2.7-GHz Survey. A total of 22 total flux density IDV sources were discovered and 15 sources were found to show IDV of their polarized flux density. We discuss the statistical properties of the IDV sources, including the distribution of source modulation indices, and the dependence of the variability amplitude on source spectral index and on Galactic position. We suggest interstellar scintillation (ISS) in the Galactic interstellar medium as the most likely mechanism for IDV. Even so, the inferred high brightness temperatures cannot be easily explained.
- ID:
- ivo://CDS.VizieR/J/PASJ/55/351
- Title:
- ATCA observations of 202 compact radio sources
- Short Name:
- J/PASJ/55/351
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Australia Telescope Compact Array (ATCA) has been used in support of the VLBI Space Observatory Programme (VSOP) space VLBI mission, to monitor the total and polarised flux densities of 202 objects that make up 83% of the VSOP all-sky Survey of compact extragalactic radio sources south of DE=+10{deg}. The primary goal of the ATCA observations is to provide information on the total and polarised emission from the compact components in these sources, for correlation with parameters obtained from VSOP imaging observations. These data represent the first high resolution, long timescale flux density monitoring observations of a large number of southern compact radio sources. In the future, comparison of the ATCA and VSOP data will be used to investigate relativistic beaming models and identify similarities or differences between the major classes of extragalactic radio sources. As an illustration of the scientific value of the ATCA data we undertake a comparison of the properties of the gamma-ray loud and gamma-ray quiet AGN in the southern component of the VSOP Survey sample, finding that in a flat-spectrum sub-sample the gamma-ray loud AGN are more variable than the gamma-ray quiet AGN.
