- ID:
- ivo://CDS.VizieR/J/AZh/84/387
- Title:
- Radio sources near North Celestial Pole
- Short Name:
- J/AZh/84/387
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the RATAN-600 radio telescope to study the spectral characteristics of a uniform sample of 504 radio sources from the NVSS catalog (Cat. VIII/65) near the North Celestial Pole at 6 frequencies from 1.1 to 21.7GHz, with the aim of selecting sources possessing inverted spectra near 22GHz, to be included in the program of the RadioAstron future space VLBI mission. We found 17 radio sources with the desired spectral characteristics. Data from spectral studies over a wide wavelength range testify that the spectral behavior of our sample differs from that for a complete sample of sources with the same initial parameters but selected at 20GHz. We find a 6% deficit of inverted-spectrum sources, which can be explained as an effect of the spectral characteristics of "sub-threshold" sources that were not included in the initial sample at 1.4GHz.
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Search Results
- ID:
- ivo://CDS.VizieR/VIII/35
- Title:
- Radio Sources observed with Culgoora Circular Array
- Short Name:
- VIII/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is a final, updated and recalibrated list of sources that were observed with the Culgoora Circular Array (CCA) in the interval 1970-1984. The list contains all the sources that were published in the Culgoora-1,2,3 Lists plus additional sources resulting from a survey of 353 Abell clusters of galaxies. The observations were made at 80 MHz and 160 MHz with HPBW in RA of 3.70' and 1.85' respectively. The beamwidth in Dec is wider by sec(30.3 + Dec). This list brings together all CCA measurements of flux density, position, spectral index and angular size, with limiting flux densities of 4 Jy at 80 MHz and 2 Jy at 160 MHz. References to the original Culgoora publications are given for each source. The sources were selected for CCA observations from the Parkes, 4C and Ohio catalogues if an extrapolation of the then existing spectral data indicated that the 80 MHz flux density would be > 5 Jy. In addition, about 300 additional sources were added from lists of special classes of objects such as those discovered at higher frequencies from surveys of the galactic plane, lists of pulsars and supernova remnants, from a list of nearby bright galaxies and finally from a CCA survey of 353 Abell clusters of galaxies. An area of 16'x16' was surveyed about the centres of 3500 fields, resulting in a total survey area of about 0.1 sr at 80 MHz.
- ID:
- ivo://CDS.VizieR/J/A+AS/131/11
- Title:
- Radio sources related to gamma-ray emission
- Short Name:
- J/A+AS/131/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 2 lists the individual flux density measurements for 47 radio sources as observed with the Effelsberg 100-m telescope.
- ID:
- ivo://CDS.VizieR/J/AJ/134/897
- Title:
- Radio sources toward galaxy clusters at 30GHz
- Short Name:
- J/AJ/134/897
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extragalactic radio sources are a significant contaminant in cosmic microwave background and Sunyaev-Zel'dovich effect experiments. Deep interferometric observations with the BIMA and OVRO arrays are used to characterize the spatial, spectral, and flux distributions of radio sources toward massive galaxy clusters at 28.5GHz. We compute counts of millijansky source fluxes from 89 fields centered on known massive galaxy clusters and 8 noncluster fields.
- ID:
- ivo://CDS.VizieR/J/MNRAS/409/821
- Title:
- Radio sources with ultrahigh polarization
- Short Name:
- J/MNRAS/409/821
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 129 unresolved radio sources with ultrahigh linear polarization (>30%) has been selected from the NRAO VLA Sky Survey. Such high average linear polarization is unusual in extragalactic sources. Higher resolution Australia Telescope Compact Array and Very Large Array observations confirm the high average polarization but find that most of these sources are extended. The Sloan Digital Sky Survey spectroscopy, where available, shows that the optical counterparts are elliptical galaxies with no detectable emission lines. The optical spectra, radio luminosity, linear size and spectral index of these sources are typical of radio-loud active galactic nuclei.
- ID:
- ivo://CDS.VizieR/J/MNRAS/474/5008
- Title:
- Radio spectral index 147-1400MHz
- Short Name:
- J/MNRAS/474/5008
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The radio spectral index is a powerful probe for classifying cosmic radio sources and understanding the origin of the radio emission. Combining data at 147MHz and 1.4GHz from the TIFR GMRT Sky Survey (TGSS) and the NRAO VLA Sky Survey (NVSS), we produced a large-area radio spectral index map of ~80 per cent of the sky (Dec. >-40deg), as well as a radio spectral index catalogue containing 1396515 sources, of which 503647 are not upper or lower limits. Almost every TGSS source has a detected counterpart, while this is true only for 36 per cent of NVSS sources. We released both the map and the catalogue to the astronomical community. The catalogue is analysed to discover systematic behaviours in the cosmic radio population. We find a differential spectral behaviour between faint and bright sources as well as between compact and extended sources. These trends are explained in terms of radio galaxy evolution. We also confirm earlier reports of an excess of steep-spectrum sources along the galactic plane. This corresponds to 86 compact and steep-spectrum source in excess compared to expectations. The properties of this excess are consistent with normal non-recycled pulsars, which may have been missed by pulsation searches due to larger than average scattering along the line of sight.
- ID:
- ivo://CDS.VizieR/J/AN/341/703
- Title:
- Radio spectral indices of active galaxies
- Short Name:
- J/AN/341/703
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we investigate radio properties of active galaxies taken from the reference Veron-Cetty & Veron (2010, Cat. VII/258) catalog. The galaxies are limited to magnitudes in the range of 12^m^-19^m^. We have cross-correlated the list with radio catalogs and selected those galaxies that have data on six or more radio fluxes at different wavelengths. As a result, we have 198 galaxies that satisfy these conditions. Using SDSS DR15, we have obtained 96 spectroscopic identifications of the 198 objects. After the classification, 85% of the 96 objects have changed their types. Available data on the classification of these objects and our classification showed that 56.7% of them are Seyfert galaxies. For all the objects, we have built radio spectra and estimated radio spectral indices. As a result, we obtain {alpha}>=-0.6089+/-0.056> ({alpha}_Seyfert_=-0.6013+/-0.027, {alpha}_LINER_=-0.5955+/-0.025, {alpha}_HII_=-0.6672+/-0.039, {alpha}_Comp._=-0.7128+/-0.043). We discuss the radio properties of active galaxies based on their radio spectral indices.
- ID:
- ivo://CDS.VizieR/J/A+A/602/A61
- Title:
- Radio spectra of globulettes in Carina nebula
- Short Name:
- J/A+A/602/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Carina nebula hosts a large number of globulettes. An optical study of these tiny molecular clouds shows that the majority are of planetary mass, but there are also those with masses of several tens up to a few hundred Jupiter masses. We seek to search for, and hopefully detect, molecular line emission from some of the more massive objects; in case of successful detection we aim to map their motion in the Carina nebula complex and derive certain physical properties. Methods.We carried out radio observations of molecular line emission in ^12^CO and ^13^CO (2-1) and (3-2) of 12 globulettes in addition to positions in adjacent shell structures using APEX. All selected objects were detected with radial velocities shifted relative to the emission from related shell structures and background molecular clouds. Globulettes along the western part of an extended dust shell show a small spread in velocity with small velocity shifts relative to the shell. This system of globulettes and shell structures in the foreground of the bright nebulosity surrounding the cluster Trumpler 14 is expanding with a few km/s relative to the cluster. A couple of isolated globulettes in the area move at similar speed. Compared to similar studies of the molecular line emission from globulettes in the Rosette nebula, we find that the integrated line intensity ratios and line widths are very different. The results show that the Carina objects have a different density/temperature structure than those in the Rosette nebula. In comparison the apparent size of the Carina globulettes is smaller, owing to the larger distance, and the corresponding beam filling factors are small. For this reason we were unable to carry out a more detailed modelling of the structure of the Carina objects in the way as performed for the Rosette objects. The Carina globulettes observed are compact and denser than objects of similar mass in the Rosette nebula. The distribution and velocities of these globulettes suggest that they have originated from eroding shells and elephant trunks. Some globulettes in the Trumpler 14 region are quite isolated and located far from any shell structures. These objects move at a similar speed as the globulettes along the shell, suggesting that they once formed from cloud fragments related to the same foreground shell.
- ID:
- ivo://CDS.VizieR/J/AJ/133/906
- Title:
- Radio star proper motions
- Short Name:
- J/AJ/133/906
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Very Large Array, linked with the Pie Town Very Long Baseline Array antenna, to determine astrometric positions of 46 radio stars in the International Celestial Reference Frame (ICRF). Positions were obtained in the ICRF directly through phase referencing of the stars to nearby ICRF quasars whose positions are accurate at the 0.25mas level. Radio star positions are estimated to be accurate at the 10mas level, with position errors approaching a few milliarcseconds for some of the stars observed. Our measured positions were combined with previous measurements taken from as early as 1978 to obtain proper-motion estimates for all 46 stars with average uncertainties of ~1.7mas/yr.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/529
- Title:
- Radio stars for linking celestial reference frames
- Short Name:
- J/A+AS/122/529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radio stars play a key role in establishing the link between optical reference frames and the conventional celestial reference frame based on extragalactic radio sources. The relevant astrometric, astrophysical and radio quantities are compiled of 66 cardinal radio stars currently suited to frame connection and main tenance of the link. The catalogue entries are supplied with ample bibliographical codes and annotations for easy data retrieval.
