- 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.
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Search Results
- 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.
- 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.
- 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.
1595. 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.
- 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.
- ID:
- ivo://CDS.VizieR/VIII/74A
- Title:
- SPECFIND Catalog of radio continuum spectra
- Short Name:
- VIII/74A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SPECFIND is a new tool to extract cross-identifications and radio continuum spectra from radio catalogues contained in the VIZIER database of the CDS. It is designed to handle radio surveys of very different resolutions and sensitivities. Power laws are fitted to the radio spectra, resulting in the determination of a power law slope and a zero-point. SPECFIND has been applied to 22 survey catalogues at 11 different frequencies (159 - 8400 MHz) containing a total of 3.5 million sources, leading to 757894 independent radio cross-identifications and 66866 independent radio spectra with more than two independent frequencies. The code was tested and its results validated by a comparison between the spectral indices found by SPECFIND and those determined by other authors. The determined spectral indices have an error of about +/-0.3. Negative spectral indices have smaller errors, while the error of positive spectral indices can be larger, mainly because of the occurrence of a peak in the spectrum. The code is quite rapid (less than 3 hr running time on a standard PC for 3.5 million sources) and since it is written in C, it can be run on virtually all PCs with at least 512~MB RAM. It produces an output of variable format that can be adapted easily to the purpose of the user. The results of the spectrum identification process are provided as a master table, where a spectrum is attached to each radio source. Due to the SPECFIND algorithm, different radio components of the same physical source can have somewhat different slopes and zero-points. The SPECFIND subdirectory contains the code (in C) and the data used to generate the catalogue, as well as a user manual (manual.ps). For compilation please IMPERATIVELY read the README file stored in the SPECFIND subdirectory.
- ID:
- ivo://CDS.VizieR/VIII/85A
- Title:
- SPECFIND V2.0 Catalog of radio continuum spectra
- Short Name:
- VIII/85A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second release of the SPECFIND catalogue. For the radio cross-identification we included 3.76 million sources from 105 VizieR radio catalogues. The SPECFIND V2.0 catalogue contains about 107000 physical objects with associated radio spectra. With an increase of 8% of available sources with respect to the first release, we could increase the number of radio objects by 60%. The results of the spectrum identification process are provided as a master table, where a spectrum is attached to each radio source. Due to the SPECFIND algorithm, different radio sources of the same physical object can have somewhat different slopes and zero-points. We also present radio sources from positional cross-identification only taking into account the source extent and the survey resolution (overlapping beams or extents). The source flux densities were not taken into account as it was done for the SPECFINDV2.0 catalogue. In this sense, it represents the waste basket of SPECFINDV2.0.
- ID:
- ivo://CDS.VizieR/VIII/104
- Title:
- SPECFIND V3.0 Catalog of radio continuum spectra
- Short Name:
- VIII/104
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Many radio continuum catalogs with different sensitivity limits and spatial resolutions are published via the VizieR database. Because of the diversity of spatial resolution, the cross-identification of individual sources is complex. By assuming a power-law spectrum, the SPECFIND tool is able to handle radio surveys at different frequencies from different instruments and different resolutions. Since the former version of the SPECFIND catalog was released ten years ago, hundreds of new radio continuum catalogs have been published. We upgraded the SPECFIND tool to reach a wider frequency range, especially the lower-frequency radio regime, as well as to have better spatial sky coverage. We adapted special selection criteria to all radio tables listed in VizieR to define a final sample of new catalogs. We implemented the new catalogs into the SPECFIND tool by unifying them and then compare the results to the last version. Furthermore we present and investigate sources with spectral breaks around 1.4GHz and around 325MHz. By increasing the number of implemented SPECFIND catalogs from 115 to 204, we improve the number of resulting spectra from 107500 to 340000 and increase the number of cross-identified sources from 600000 to 1.6 million. Furthermore, we present two samples of spectral break sources. The first sample includes 3104 spectral break sources with turnover frequencies around 1.4GHz, the second sample includes 18075 spectral break sources with turnover frequencies around 325MHz. Both samples include concave sources and Gigaherz-Peaked Spectrum (GPS) or Megaherz-Peaked Spectrum (MPS) sources. The SPECFIND V3.0 catalog is a very useful resource and a powerful open access tool, reachable via VizieR. By tripling the resulting spectra and including many radio continuum surveys from the last 50 years, we provide a significantly extended catalog of cross-identified radio continuum sources. Furthermore, the SIMBAD database will be updated using the SPECFIND V3.0 catalog and will contain more radio continuum data, serving the needs of future projects.
- ID:
- ivo://CDS.VizieR/VIII/33
- Title:
- Spectral characteristics of RATAN (RC) Catalog
- Short Name:
- VIII/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spectral analysis of the RC-catalog of the experiment "Cold" containing 840 radiosources in the interval of right ascension 4-22h are made. 280 spectra of radiosources are presented; 215 spectra are new. The mean spectral index for 196 objects with steep spectra (alpha >= 0 5) and flux densities >12mJy is 0.87+/-0.01. The preliminary optical identification of radiosources with catalogued galaxies is done.
