- ID:
- ivo://CDS.VizieR/J/ApJ/589/733
- Title:
- VLBI polarimetry of CJF sources
- Short Name:
- J/ApJ/589/733
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Very Long Baseline Array observations and a statistical analysis of 5GHz VLBI polarimetry data from 177 sources in the Caltech-Jodrell Bank Flat-Spectrum (CJF) survey. The CJF survey, a complete, flux density-limited sample of 293 extragalactic radio sources, gives us the unique opportunity to compare a broad range of source properties for quasars, galaxies, and BL Lacertae objects. We focus primarily on jet properties, specifically, the correlation between the jet axis angle and the polarization angle in the core and jet. A strong correlation is found for the electric vector polarization angle in the cores of quasars to be perpendicular to the jet axis. Contrary to previous claims, no correlation is found between the jet polarization angle and the jet axis in either quasars or BL Lac objects. With this large, homogeneous sample we are also able to investigate cosmological issues and active galactic nucleus evolution.
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- ID:
- ivo://CDS.VizieR/J/AZh/81/1032
- Title:
- VLBI Position Measurements
- Short Name:
- J/AZh/81/1032
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large number (~2 million) of VLBI observations have been reduced in order to re ne the measured coordinates of the observed radio sources. The data reduction was carried out in the OCCAM package using the least squares colocation method. Corrections to the coordinates of 642 objects were derived. The accuracy of the catalog is no worse than 0.2 milliseconds of arc for stable sources.
- ID:
- ivo://CDS.VizieR/J/ApJ/673/78
- Title:
- VLBI suvey around B0218+357 at 90cm
- Short Name:
- J/ApJ/673/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the first wide-field, very long baseline interferometry (VLBI) survey at 90cm. The survey area consists of two overlapping 28deg^2^ fields centered on the quasar J0226+3421 and the gravitational lens B0218+357. A total of 618 sources were targeted in these fields, based on identifications from Westerbork Northern Sky Survey (WENSS) data. Of these sources, 272 had flux densities that, if unresolved, would fall above the sensitivity limit of the VLBI observations. A total of 27 sources were detected as far as 2{deg} from the phase center. The results of the survey suggest that at least 10% of moderately faint (S~100mJy) sources found at 90 cm contain compact components smaller than ~0.1"-0.3" and stronger than 10% of their total flux densities.
- ID:
- ivo://CDS.VizieR/J/A+A/463/519
- Title:
- VVDS-VLA Deep Field: 610 MHz catalog
- Short Name:
- J/A+A/463/519
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the 5 sigma catalogue at 610MHz of the VVDS-VLA deep field obtained from GMRT observations. The field is located at 02:26:00-04:30:00 (J2000) and covers a 1 square degree area. The GMRT observations imaged the whole 1 square degree field with an angular resolution of 6 arcsec and an average sensitivity of about 50 microJy. The catalogue lists 514 radio sources 17 of which are fitted with multiple components.
- ID:
- ivo://CDS.VizieR/J/MNRAS/473/1685
- Title:
- Weak Galactic radio sources spectral indices
- Short Name:
- J/MNRAS/473/1685
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the next few years the classification of radio sources observed by the large surveys will be a challenging problem and spectral index is a powerful tool for addressing it. Here we present an algorithm to estimate the spectral index of sources from multiwavelength radio images. We have applied our algorithm to SCORPIO, a Galactic plane survey centred around 2.1GHz carried out with Australian Telescope Compact Array and found we can measure reliable spectral indices only for sources stronger than 40 times the rms noise. Above a threshold of 1mJy, the source density in SCORPIO is 20 per cent greater than in a typical extragalactic field, like Australia Telescope Large Area Survey because of the presence of Galactic sources. Among this excess population, 16 sources per square degree have a spectral index of about zero suggesting optically thin thermal emission such as HII regions and planetary nebulae, while 12 per square degree present a rising spectrum, suggesting optically thick thermal emission such as stars and UCHII regions.
- ID:
- ivo://CDS.VizieR/J/A+AS/124/259
- Title:
- Westerbork Northern Sky Survey I.
- Short Name:
- J/A+AS/124/259
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Westerbork Nortern Sky Survey (WENSS) is a low-frequency (325 MHz) radio survey that will cover the whole sky north of a declination of 30 degrees A first installment of the survey covers an area of 570 square degrees around the North Ecliptic Pole. A source list comprising 11,299 sources and 994 components is listed in Table 6 of the paper. This table is presented here.
- ID:
- ivo://CDS.VizieR/J/A+AS/43/1
- Title:
- Westerbork observations of Galactic Sources
- Short Name:
- J/A+AS/43/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for new Galactic sources from the BG catalogue (Fanti et al., 1974A&AS...16...43F). The observations were made with the Westerbork Synthesis Radiotelescope operating at 1.4GHz, using the short cuts technique. The adopted selection criteria for the observed sample are discussed in detail. For reducing the data we have adopted the Clean and Restore technique. We have also tested the capability of this technique in reproducing the total flux density for the very extended structures. A catalogue of the sources present in each field was produced ; the relevant information about observations and reduction characteristics are given.
- ID:
- ivo://CDS.VizieR/J/A+A/35/393
- Title:
- Westerbork Second Deep Survey
- Short Name:
- J/A+A/35/393
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A radio survey has been made of an area centered at 01h 03min +29{deg}, using the Westerbork telescope at 1415MHz. The completeness limit of the survey is 7mJy. Additional observations have been made at 610MHz. The Lick 120" telescope has been used to obtain deep (O98-O2 emulsion) plates to serve as an optical counterpart. A catalogue is presented of 58 sources found in the survey. 53 of these comprise a complete sample. 31 sources of the complete sample lie in areas of which Lick plates were taken. Of the sources in Lick plates areas, 11 could be identified with galaxies and 3 with possible QSO's, yielding an identification percentage of 46. For the other 22 sources an identification programme was carried out using Palomar Sky Survey prints and other large 48" Schmidt plates: three of these sources could be identified with galaxies and two with possible QSO's. The survey was also used to derive source counts and a spectral index distribution. The source counts agree well with those derived for an earlier survey. The spectral index distribution has a mean of 0.52 and a width of 0.39. the explanation for the flatter spectra is not clear but might possibly lie in another source population that begins to dominate the results at low flux densities.
- ID:
- ivo://CDS.VizieR/VIII/64
- Title:
- Westerhout's Catalogue of 82 Discrete Sources
- Short Name:
- VIII/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue was created based on the original published catalogue in the article by Westerhout G., 1958, Bull. Astron. Inst. Netherlands, vol.14, p.215, "A Survey of the Continuous Radiation from the Galactic System at a Frequency of 1390 Mc/s." His article describes the results of a survey of the radiation along the galactic ridge and a search for discrete sources. The observations were made with the 25-m radio telescope at Dwingeloo, which has a beamwidth of 0.57 degree at a frequency of 1390 Mc/s. The catalogue contains positions of 82 discrete sources. The epoch for positions in the original published catalogue was 1957.0. Positions referred to 2000.0 are shown in this machine-readable catalogue.
- ID:
- ivo://CDS.VizieR/J/ApJS/215/14
- Title:
- WISE candidate {gamma}-ray blazar radio sources
- Short Name:
- J/ApJS/215/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of radio-loud candidate {gamma}-ray emitting blazars with WISE mid-infrared colors similar to the colors of confirmed {gamma}-ray blazars. The catalog is assembled from WISE sources detected in all four WISE filters, with colors compatible with the three-dimensional locus of the WISE {gamma}-ray emitting blazars, and which can be spatially cross-matched with radio sources from one of the three radio surveys: NVSS, FIRST, and/or SUMSS. Our initial WISE selection uses a slightly modified version of previously successful algorithms. We then select only the radio-loud sources using a measure of the radio-to-IR flux, the q_22_parameter, which is analogous to the q_24_ parameter known in the literature but which instead uses the WISE band-four flux at 22{mu}m. Our final catalog contains 7855 sources classified as BL Lacs, FSRQs, or mixed candidate blazars; 1295 of these sources can be spatially re-associated as confirmed blazars. We describe the properties of the final catalog of WISE blazar-like radio-loud sources and consider possible contaminants. Finally, we discuss why this large catalog of candidate {gamma}-ray emitting blazars represents a new and useful resource to address the problem of finding low-energy counterparts to currently unidentified high-energy sources.