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2971. Radio sources at 0.327, 1.4, 4.5, 8.5GHz
ID:
ivo://CDS.VizieR/J/ApJ/686/859
Title:
Radio sources at 0.327, 1.4, 4.5, 8.5GHz
Short Name:
J/ApJ/686/859
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of the energetics and particle content of the lobes of 24 radio galaxies at the cores of cooling clusters. The radio lobes in these systems have created visible cavities in the surrounding hot, X-ray-emitting gas, which allow direct measurement of the mechanical jet power of radio sources over six decades of radio luminosity, independently of the radio properties themselves. We find that jet (cavity) power increases with radio synchrotron power approximately as P_jet_~L^{beta}^_radio_, where 0.35<={beta}<=0.70 depending on the bandpass of measurement and state of the source. Furthermore, we place limits on the magnetic field strengths and particle content of the radio lobes using a variety of X-ray constraints. We find that the lobe magnetic field strengths vary between a few to several tens of microgauss depending on the age and dynamical state of the lobes.
2972. Radio sources at 8.5GHz
ID:
ivo://CDS.VizieR/J/ApJ/635/950
Title:
Radio sources at 8.5GHz
Short Name:
J/ApJ/635/950
Date:
21 Oct 2021
Publisher:
CDS
Description:
Most currently available counts of radio sources at frequencies >5GHz are restricted to relatively bright sources. Observations made at NRAO's VLA have, however, provided counts of very faint sources (S<~1mJy) at 8.5GHz. Here we extend the 8.5GHz VLA source counts to higher flux densities using both archival data and a brief, blind VLA survey at 8.5GHz.
2973. Radio Sources in Low-Luminosity AGNs. IV
ID:
ivo://CDS.VizieR/J/A+A/435/521
Title:
Radio Sources in Low-Luminosity AGNs. IV
Short Name:
J/A+A/435/521
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the completed results of a high resolution radio imaging survey of all (~200) low-luminosity active galactic nuclei (LLAGNs) and AGNs in the Palomar Spectroscopic Sample of all (~488) bright northern galaxies. The high incidences of pc-scale radio nuclei, with implied brightness temperatures >~10^7K, and sub-parsec jets argue for accreting black holes in >=50% of all LINERs and low-luminosity Seyferts; there is no evidence against all LLAGNs being mini-AGNs. The detected parsec-scale radio nuclei are preferentially found in massive ellipticals and in type 1 nuclei (i.e. nuclei with broad Halpha emission). The radio luminosity function (RLF) of Palomar Sample LLAGNs and AGNs extends three orders of magnitude below, and is continuous with, that of 'classical' AGNs. We find marginal evidence for a low-luminosity turnover in the RLF; nevertheless LLAGNs are responsible for a significant fraction of present day mass accretion.
2974. Radio spectra of HDF850.1
ID:
ivo://CDS.VizieR/J/A+A/562/A35
Title:
Radio spectra of HDF850.1
Short Name:
J/A+A/562/A35
Date:
21 Oct 2021
Publisher:
CDS
Description:
New high-resolution maps with the IRAM interferometer of the redshifted C+ 158um line and the 0.98mm dust continuum of HDF850.1 at z=5.185 show the source to have a blueshifted northern component and a redshifted southern component, with a projected separation of 0.3", or 2kpc. We interpret these components as primordial galaxies that are merging to form a larger galaxy.
2975. Radio study of double-double radio galaxy 3C293
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.
2976. Radio survey of the 1H XMM/Chandra field
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.
2977. Radio Survey of 7 X-ray Clusters of Galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/391/297
Title:
Radio Survey of 7 X-ray Clusters of Galaxies
Short Name:
J/MNRAS/391/297
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Australia Telescope Compact Array (ATCA) has been used at 1.38 and 2.38GHz to survey seven southern Abell clusters of galaxies with high X-ray luminosities: A2746, A2837, A3126, A3216, A3230, A3827 and A3836. The clusters have also been surveyed at 0.843GHz with the Molonglo Observatory Synthesis Telescope (MOST). We have listed a complete 1.38-GHz sample of 149 radio sources within the Abell circles centred on their X-ray centroids. We compare their identification fractions, emitted 1.38-GHz and optical powers, radio spectral indices and radial variation in projected source density with those of the radio-selected samples of Slee et al. (1998AuJPh..51..971S). We compare our fractional radio luminosity function with that of the radio-selected samples of Ledlow and Owen (1996AJ....112....9L) and Slee et al. (1998AuJPh..51..971S). Three significant differences are noted between X-ray and radio-selected samples of clusters; (1) the X-ray sample has an excess of flat-spectrum radio sources; (2) the fractional radio luminosity function for the FR I sources in the X-ray selected sample is much steeper, implying that fewer of their cluster galaxies become hosts for the stronger FR I radio galaxies; (3) a complete absence of FR II radio galaxies in the X-ray selected sample. The average excess projected density of radio sources near our cluster centres is approx. 5 times the background source density.
2978. Radio time delay of gravitational lens 0957+561
ID:
ivo://CDS.VizieR/J/ApJ/510/64
Title:
Radio time delay of gravitational lens 0957+561
Short Name:
J/ApJ/510/64
Date:
21 Oct 2021
Publisher:
CDS
Description:
The gravitational lens 0957+561 was monitored with the Very Large Array from 1979 to 1997. The 6 cm light-curve data from 1995 to 1997 and the 4cm data from 1990 to 1997 are reported here. At 4cm the intrinsic source variations occur earlier and are twice as large as the corresponding variations at 6cm. The VLBI core and jet components have different magnification factors, leading to different flux ratios for the varying and nonvarying portions of the VLA light curves. Using both the Press, Rybicki, & Hewitt Q (1992ApJ...385..404P) and dispersion statistical techniques, we determined the time delay, core flux ratio, and excess nonvarying B image flux density. The fits were performed for the 4 and 6 cm light curves, both individually and jointly, and we used Gaussian Monte Carlo data to estimate 68% statistical confidence levels. The delay estimates from each individual wavelength were inconsistent given the formal uncertainties, suggesting that there are unmodeled systematic errors in the analysis. We roughly estimate the systematic uncertainty in the joint result from the difference between the 6 and 4cm results, giving 409+/-30 days for the PRHQ statistic and 397+/-20 days for the dispersion statistic. These results are consistent with the current optical time delay of 417+/-3 days, reconciling the long-standing difference between the optical and radio light curves and between different statistical analyses.
2979. Radio transients in a 1.4GHz drift-scan survey
ID:
ivo://CDS.VizieR/J/ApJ/704/652
Title:
Radio transients in a 1.4GHz drift-scan survey
Short Name:
J/ApJ/704/652
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report two new radio transients at high Galactic latitude, WJN J0951+3300 (RA=09h51m22s+/-10s, DE=33{deg}00'+/-0.4{deg}, b=50{deg}54.2') and WJN J1039+3300 (RA=10h39m26s+/-10s, DE=33{deg}00'+/-0.4{deg}, b=60{deg}58.5'), which were detected by interferometric drift-scan observations at 1.4GHz at the Waseda Nasu Pulsar Observatory. WJN J0951+3300 was detected at 16:49:32UT on 2006 January 12 with the flux density of approximately 1760.5+/-265.9mJy, and WJN J1039+3300 was detected at 17:13:32UT on 2006 January 18 with the flux density of approximately 2242.5+/-228.7mJy. Both of them lasted for a short duration (<=2 days). The possibility that the distribution of the WJN radio transients is isotropic was suggested in a previous study. Having re-evaluated the log N-log S relation with the addition of the two new objects reported in this paper, we find that the slope is consistent with a slope of -1.5 and the previous result. Additionally, although there are several counterparts to WJN radio transients, we found that one of the quasar counterparts within the positional error of WJN J0951+3300 could be a radio-loud quasar. We have discussed whether or not WJN J0951+3300 could be of this quasar origin.
2980. RASS: clusters of galaxies around SGP
ID:
ivo://CDS.VizieR/J/ApJS/140/239
Title:
RASS: clusters of galaxies around SGP
Short Name:
J/ApJS/140/239
Date:
21 Oct 2021
Publisher:
CDS
Description:
A field of 1.013sr in the ROSAT All-Sky Survey (RASS), centered on the south Galactic pole (SGP), has been searched in a systematic, objective manner for clusters of galaxies. The procedure relied on a correlation of the X-ray positions and properties of ROSAT sources in the field with the distribution of galaxies in the COSMOS digitized database, which was obtained from scanning the plates of the UK Schmidt IIIa-J optical survey of the southern sky. The study used the second ROSAT survey database (RASS-2) and included several optical observing campaigns to measure cluster redshifts. The search, which is a precursor to the larger REFLEX survey encompassing the whole southern sky, reached the detection limits of both the RASS and the COSMOS data and yielded a catalog of 186 clusters in which the lowest flux is 1.5x10-12ergs/cm^2^/s in the 0.1-2.4keV band. Of these 157 have measured redshifts. Using a flux limit of 3.0x10-12ergs/cm^2^/s a complete subset of 112 clusters was obtained, of which 110 have measured redshifts. The spatial distribution of the X-ray clusters out to a redshift of 0.15 shows an extension of the Local Supercluster to the Pisces-Cetus supercluster (z<0.07), and an orthogonal structure at higher redshift (0.07<z<0.15). This result is consistent with large-scale structure suggested by optical surveys.