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Start Over Subject radio astronomy Publisher CDS
1581. Sources from the WMAP catalog
ID:
ivo://CDS.VizieR/J/AZh/85/483
Title:
Sources from the WMAP catalog
Short Name:
J/AZh/85/483
Date:
21 Oct 2021
Publisher:
CDS
Description:
Observations of a complete sample of sources from the WMAP catalog were obtained at 22.2 and 36.8GHz on the RT-22 radio telescope of the Crimean Astrophysical Observatory. We have determined the distribution of the source spectral indices between these frequencies. The distributions of the spectral indices of the WMAP catalog (between 23 and 33GHz) and in the RT-22 sample have the same shape and half-width, suggesting that the mean source parameters are constant in time. We have plotted the logN-logS dependence down to the flux levels of about 0.1Jy using pilot data from the AT20 survey, where a cosmological "cutoff" in the source counts is already observed. The variability of individual sources in connection with flare activity is considered. The optical characteristics of the complete sample of WMAP sources are compared to those of identified AT20 survey sources.
1582. Sources in VSA fields at 30GHz
ID:
ivo://CDS.VizieR/J/MNRAS/406/1853
Title:
Sources in VSA fields at 30GHz
Short Name:
J/MNRAS/406/1853
Date:
21 Oct 2021
Publisher:
CDS
Description:
Small angular scale (high multipole order l) studies of cosmic microwave background (CMB) anisotropies require accurate knowledge of the statistical properties of extragalactic sources at cm-mm wavelengths. We have used a 30GHz dual-beam receiver (One Centimetre Receiver Array prototype) on the Torun 32-m telescope to measure the flux densities of 121 sources in Very Small Array fields selected at 15GHz with the Ryle Telescope. We have detected 57 sources above a limiting flux density of 5mJy, of which 31 sources have a flux density greater than 10mJy, which is our effective completeness limit. From these measurements we derive a surface density of sources above 10mJy at 30GHz of 2.2+/-0.4deg^-2^. This is consistent with the surface density obtained by Mason et al. who observed a large sample of sources selected at a much lower frequency (1.4GHz). We have also investigated the dependence of the spectral index distribution on flux density by comparing our results with those for sources above 1Jy selected from the Wilkinson Microwave Anisotropy Probe 22GHz catalogue.
1583. 90 sources radio flux density from GLEAM and HERA
ID:
ivo://CDS.VizieR/J/ApJ/897/5
Title:
90 sources radio flux density from GLEAM and HERA
Short Name:
J/ApJ/897/5
Date:
16 Mar 2022 00:49:20
Publisher:
CDS
Description:
The central challenge in 21cm cosmology is isolating the cosmological signal from bright foregrounds. Many separation techniques rely on the accurate knowledge of the sky and the instrumental response, including the antenna primary beam. For drift-scan telescopes, such as the Hydrogen Epoch of Reionization Array (HERA), that do not move, primary beam characterization is particularly challenging because standard beam-calibration routines do not apply (Cornwell et al.) and current techniques require accurate source catalogs at the telescope resolution. We present an extension of the method from Pober et al. where they use beam symmetries to create a network of overlapping source tracks that break the degeneracy between source flux density and beam response and allow their simultaneous estimation. We fit the beam response of our instrument using early HERA observations and find that our results agree well with electromagnetic simulations down to a -20dB level in power relative to peak gain for sources with high signal-to-noise ratio. In addition, we construct a source catalog with 90 sources down to a flux density of 1.4Jy at 151MHz.
1584. Southern Extragalactic Radio Sources
ID:
ivo://CDS.VizieR/J/ApJS/80/137
Title:
Southern Extragalactic Radio Sources
Short Name:
J/ApJS/80/137
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalog contains a list of 384 extragalactic radio sources south of declination -30{deg} which have been imaged with the Molonglo Observatory Synthesis Telescope (MOST) at 843 MHz with a HPBW of 44" x 44" cosec(dec). The sample includes those sources noted in the Molonglo Reference Catalog (MRC) (Cat.<VIII/16>) as extended (larger than 1'), as well as those noted as multiple (within 8' of another ssource and possibly related). The sample is representative of the strong extended extragalactic radio sources of the southern sky, but is not statistically complete. Positions, flux densities, and sizes are given for all sources, and those sources which have been confirmed as extended MRC sources are flagged. In addition, optical positions, magnitudes, redshifts, and identifications are given for 201 of the sources. These data were originally published in two tables which have been merged in this version.
1585. Southern flat-spectrum sources
ID:
ivo://CDS.VizieR/VIII/45
Title:
Southern flat-spectrum sources
Short Name:
VIII/45
Date:
21 Oct 2021
Publisher:
CDS
Description:
Optical identifications have been sought for 198 southern radio sources (73 in Paper I, 06h<RA(B1950)<18h and 125 in Paper II, 18h<RA(B1950)<06h) using new positions determined with the six-dish array of the Fleurs synthesis telescope. These sources constitute a complete sample drawn from the Parkes 2700-MHz catalogue. They are all flat-spectrum sources stronger than 0.25 Jy at 2700 MHz and lie between Dec(B1950) -80 and -50{deg}. Sources with |b|<5{deg} are not included. The new radio positions have standard deviations of about 1'' (2'' in Paper I, 1'' in Paper II) in right ascension and declination. The optical positions are with respect to the FK4 reference system as defined by the Perth catalogues and have position uncertainties of about 0.5arcsec. Magnitude estimates are on the J scale and are accurate to about 0.4mag for stellar-like objects and 0.5 to 1.0mag for galaxies. The sample is complete to the 22.5-mag limit of the SERC-J sky atlas. There are 198 sources in the complete sample. 31 sources (16%) show some radio structure with the 2'' beam. For the 175 unresolved sources, there are 124 QSOs (71%), 26 galaxies (15%) and 25 empty fields (14%) suggested.
1586. Southern H II Region Discovery Survey: pilot survey
ID:
ivo://CDS.VizieR/J/AJ/154/23
Title:
Southern H II Region Discovery Survey: pilot survey
Short Name:
J/AJ/154/23
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Southern H II Region Discovery Survey is a survey of the third and fourth quadrants of the Galactic plane that will detect radio recombination line (RRL) and continuum emission at cm-wavelengths from several hundred H II region candidates using the Australia Telescope Compact Array. The targets for this survey come from the WISE Catalog of Galactic H II Regions (Anderson et al. 2014, J/ApJS/212/1) and were identified based on mid-infrared and radio continuum emission. In this pilot project, two different configurations of the Compact Array Broad Band receiver and spectrometer system were used for short test observations. The pilot surveys detected RRL emission from 36 of 53 H II region candidates, as well as seven known H II regions that were included for calibration. These 36 recombination line detections confirm that the candidates are true H II regions and allow us to estimate their distances.
1587. Southern methanol masers at 36 and 44GHz
ID:
ivo://CDS.VizieR/J/MNRAS/439/2584
Title:
Southern methanol masers at 36 and 44GHz
Short Name:
J/MNRAS/439/2584
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Australia Telescope Compact Array (ATCA) has been used for high angular resolution imaging of 71 southern class I methanol maser sources quasi-simultaneously at 36 and 44GHz. The data reveal a high level of morphological and kinematical complexity, and allow us to demonstrate associations, at arcsecond precision, of the class I maser emission with outflows, expanding HII regions, dark clouds, shocks traced by the 4.5-micron emission and 8.0-micron filaments. More than 700 maser component features were found at each of the two methanol transitions, but with only 23 per cent recognisable at both transitions; the morphology of class I emission is much better revealed by our survey of both transitions, compared with either one alone. We found that the number of masers falls exponentially with the projected linear distance from the associated class II 6.7-GHz methanol maser. This distribution has a scale of 263+/-15-milliparsec, irrespective of the transition. The class I masers associated with OH masers were found to have a tendency to be more spread out, both spatially and in the velocity domain. This is consistent with the expectation that such sources are more evolved. Apart from a small number of high-velocity components (which are largely blue-shifted and predominantly seen at 36GHz), the velocity distribution was found to be Gaussian, peaking near the systemic velocity of the region, which had been estimated as the middle of the velocity interval of the associated class II methanol maser at 6.7GHz. The mean indicated a small, but significant blue shift asymmetry of -0.57km/s (uncertainties are 0.06 and 0.07km/s for the 36- and 44-GHz masers, respectively) with respect to the 6.7GHz masers. The standard deviation of the velocity distribution was found to be 3.65+/-0.05 and 3.32+/-0.07km/s for the 36- and 44GHz masers, respectively. We also suggest a refined rest frequency value of 36169.238+/-0.011MHz for the 4_-1_-3_0_E methanol transition.
1588. Southern radio sources catalog
ID:
ivo://CDS.VizieR/J/other/PASAu/10.140
Title:
Southern radio sources catalog
Short Name:
J/other/PASAu/10
Date:
21 Oct 2021
Publisher:
CDS
Description:
A list of 900 radio sources with positional accuracies better than 0.5" has been prepared from seventeen lists of radio source positions found in the literature. This compilation includes all such sources south of declination +48{deg} (the northern declination limit of the Compact Array of the Australia Telescope National Facility). Where available, optical identifications, optical magnitudes and redshifts are given as well as total-power flux densities.
1589. S-PASS catalog at 2.3GHz
ID:
ivo://CDS.VizieR/J/other/PASA/34.13
Title:
S-PASS catalog at 2.3GHz
Short Name:
J/other/PASA/34.
Date:
21 Oct 2021
Publisher:
CDS
Description:
The S-band Polarisation All-Sky Survey (S-PASS) has observed the entire southern sky using the 64-metre Parkes radio telescope at 2.3GHz with an effective bandwidth of 184MHz. The surveyed sky area covers all declinations DE<0{deg}. To analyse compact sources the survey data have been re-processed to produce a set of 107 Stokes I maps with 10.75-arcmin resolution and the large scale emission contribution filtered out. In this paper we use these Stokes I images to create a total intensity southern-sky extragalactic source catalogue at 2.3GHz. The source catalogue contains 23389 sources and covers a sky area of 16600deg^2^, excluding the Galactic plane for latitudes |b|<10{deg}. Approximately 8% of catalogued sources are resolved. S-PASS source positions are typically accurate to within 35-arcsec. At a flux density of 225mJy the S-PASS source catalogue is more than 95% complete, and ~94% of S-PASS sources brighter than 500mJy/beam have a counterpart at lower frequencies.
1590. S-PASS & NVSS bright extragalactic radio sources
ID:
ivo://CDS.VizieR/J/ApJ/829/5
Title:
S-PASS & NVSS bright extragalactic radio sources
Short Name:
J/ApJ/829/5
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a polarization catalog of 533 extragalactic radio sources that have a 2.3GHz total intensity above 420mJy from the S-band Polarization All Sky Survey, S-PASS, with corresponding 1.4GHz polarization information from the NRAO VLA Sky Survey, NVSS. We studied the selection effects and found that fractional polarization, {pi}, of radio objects at both wavelengths depends on the spectral index, the source magnetic field disorder, the source size, and depolarization. The relationship between depolarization, spectrum, and size shows that depolarization occurs primarily in the source vicinity. The median {pi}_2.3_ of resolved objects in NVSS is approximately two times larger than that of unresolved sources. Sources with little depolarization are ~2 times more polarized than both highly depolarized and re-polarized sources. This indicates that intrinsic magnetic field disorder is the dominant mechanism responsible for the observed low fractional polarization of radio sources at high frequencies. We predict that number counts from polarization surveys will be similar at 1.4GHz and at 2.3GHz, for fixed sensitivity, although ~10% of all sources may currently be missing because of strong depolarization. Objects with {pi}_1.4_~{pi}_2.3_>=4% typically have simple Faraday structures, so they are most useful for background samples. Almost half of flat-spectrum ({alpha}>=-0.5) and ~25% of steep-spectrum objects are re-polarized. Steep-spectrum, depolarized sources show a weak negative correlation of depolarization with redshift in the range 0<z<2.3. Previous non-detections of redshift evolution are likely due the inclusion of re-polarized sources as well.

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