- 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.
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- 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.
- ID:
- ivo://CDS.VizieR/J/AJ/108/1163
- Title:
- Radio structure of Quasars
- Short Name:
- J/AJ/108/1163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Images of resolved radio sources in the Palomar Bright Quasar Survey are presented with an angular resolution of 0.5 and 18arcsec. The observed structure of some well resolved radio quiet quasars and AGN's show large scale linear structures or unresolved central cores similar to radio loud objects in the BQS sample as well as the more luminous radio selected quasars. We suggest that at least some of these less luminous radio quiet objects may contain compact central engines characteristic of radio loud quasars and radio galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/1397
- Title:
- Radio study of double-double radio galaxy 3C293
- Short Name:
- J/MNRAS/414/1397
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radio continuum observations at frequencies ranging from ~150 to 5000MHz of the misaligned double-double radio galaxy (DDRG) 3C 293 (J1352+3126) using the Giant Metrewave Radio Telescope (GMRT) and the Very Large Array (VLA). The spectra of the outer lobes and the central source are consistent with being straight, indicating spectral ages of <~17-23Myr for the outer lobes and <~0.1Myr for the central source. The north-western lobe has a prominent hotspot suggesting that the interruption of jet activity is <~0.1Myr, consistent with the age of the inner double. The time-scale of interruption of jet activity appears significantly smaller than observed in most other DDRGs which are often associated with giant radio sources. These observations suggest that there is a wide range of time-scales of interruption of jet activity in active galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/93/145
- Title:
- Radio survey around North Ecliptic Pole
- Short Name:
- J/ApJS/93/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A 29.3deg^2 region surrounding the north ecliptic pole (NEP; R.A.=18h00m, Dec.=+66d30m) was mapped with the Very Large Array at 1.5GHz to support the deepest portion of the ROSAT all-sky soft X-ray survey. The resulting VLA-NEP survey catalog contains 2435 radio sources with flux densities in the range of 0.3-1000mJy, including over 200 fainter than 1mJy. The 28 fields of the inner 1.5deg have noise levels sigma ~=60uJy, and the 85 fields centered between 1.5deg and 3.0deg from the NEP have sigma ~=120uJy. The typical spatial resolution is 20" HPBW, and most positions are accurate to <2". Approximately 6% of the sources are found to be extended with size >30". We have compared the VLA-NEP catalog with four other radio catalogs made at lower resolution, as well as with the NASA Extragalactic Database and find counterparts for ~18% of the VLA-NEP objects. The normalized, differential radio source count is in agreement with the previous studies. Between 1 and 150mJy the slope of the logN-logS relation is 0.68+/-0.03.
- ID:
- ivo://CDS.VizieR/VIII/43
- Title:
- Radio survey of clusters of galaxies
- Short Name:
- VIII/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of Abell clusters at 11.1, 6.2, 6.3 and 2.8cm with the 100m Effelsberg telescope. The data were compiled by H.J. Andernach.
- ID:
- ivo://CDS.VizieR/J/MNRAS/378/995
- Title:
- Radio survey of the 1H XMM/Chandra field
- Short Name:
- J/MNRAS/378/995
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a deep 610-MHz survey of the 1^H^ XMM-Newton/Chandra survey area with the Giant Metre-wave Radio Telescope. The resulting maps have a resolution of ~7arcsec and an rms noise limit of 60Jy. To a 5{sigma} detection limit of 300Jy, we detect 223 sources within a survey area of 64arcmin in diameter. We compute the 610-MHz source counts and compare them to those measured at other radio wavelengths.
- ID:
- ivo://CDS.VizieR/J/A+A/549/A131
- Title:
- Radio survey of ultracool dwarfs
- Short Name:
- J/A+A/549/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to increase the sample of ultracool dwarfs studied in the radio domain to allow a more statistically significant understanding of the physical conditions associated with these magnetically active objects. We conducted a volume-limited survey at 4.9GHz of 32 nearby ultracool dwarfs with spectral types covering the range M7-T8. A statistical analysis was performed on the combined data from the present survey and previous radio observations of ultracool dwarfs.
