- 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.
Number of results to display per page
Search Results
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
