- ID:
- ivo://CDS.VizieR/J/MNRAS/371/963
- Title:
- Deep VLA survey in Lockman Hole, HDFN, ELAIS N2
- Short Name:
- J/MNRAS/371/963
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present catalogues of faint 1.4-GHz radio sources from extremely deep Very Large Array pointings in the Lockman Hole, the Hubble Deep Field-North (HDF-N) and the European Large Area ISO Survey (ELAIS) N2 field. Our analysis of the HDF-N data has produced maps that are significantly deeper than those previously published, and we have used these to search for counterparts to submillimetre sources. For each of the fields, we have derived normalized differential source counts and in the case of the HDF-N find no evidence for the previously reported underdensity of sources; our counts are entirely consistent with those found for the majority of other fields. The catalogues are available as an online supplement to this paper and the maps are also available for download.
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- ID:
- ivo://CDS.VizieR/J/AJ/115/1253
- Title:
- Deep X-Ray Radio Blazar Survey (DXRBS). I.
- Short Name:
- J/AJ/115/1253
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have undertaken a survey, the Deep X-Ray Radio Blazar Survey (DXRBS), of archived, pointed ROSAT Position Sensitive Proportional Counter data for blazars by correlating the ROSAT WGACAT database with several publicly available radio catalogs, restricting our candidate list to serendipitous flat radio spectrum sources ({alpha}_r_<=0.70, where S_{nu}_{prop}{nu}^-{alpha}_r_^). We discuss our survey methods, identification procedure, and first results. Our survey is found to be 95% efficient at finding flat-spectrum radio-loud quasars (FSRQs; 59 of our first 85 identifications) and BL Lacertae objects (22 of our first 85 identifications), a figure that is comparable to or greater than that achieved by other radio and X-ray survey techniques. The identifications presented here show that all previous samples of blazars (even when taken together) did not representatively survey the blazar population, missing critical regions of (LX, LR) parameter space within which large fractions of the blazar population lie. Particularly important is the identification of a large population of FSRQs (>=25% of DXRBS FSRQs) with ratios of X-ray to radio luminosity >=10^-6^({alpha}_rx_<=0.78). In addition, as a result of our greater sensitivity, the DXRBS has already more than doubled the number of FSRQs in complete samples with 5GHz (radio) luminosities between 10^31.5^ and 10^33.5^ergs/s/Hz, and fills in the region of parameter space between X-ray-selected and radio-selected samples of BL Lac objects. The DXRBS is the very first sample to contain statistically significant numbers of blazars at low luminosities, approaching what should be the lower end of the FSRQ luminosity function.
- ID:
- ivo://CDS.VizieR/J/MNRAS/323/757
- Title:
- Deep X-Ray Radio Blazar Survey (DXRBS). II.
- Short Name:
- J/MNRAS/323/757
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have searched the archived, pointed ROSAT Position Sensitive Proportional Counter data for blazars by correlating the WGACAT X-ray data base with several publicly available radio catalogues, restricting our candidate list to serendipitous X-ray sources with a flat radio spectrum ({alpha}_r_<=0.70, where S_{nu}_~{nu}^-{alpha}^). his makes up the Deep X-ray Radio Blazar Survey (DXRBS). Here we present new identifications and spectra for 106 sources, including 86 radio-loud quasars, 11 BL Lacertae objects, and nine narrow-line radio galaxies. Together with our previously published objects and already-known sources, our sample now contains 298 identified objects: 234 radio-loud quasars [181 flat-spectrum quasars: FSRQ ({alpha}_r_<=0.50) and 53 steep-spectrum quasars: SSRQ], 36 BL Lacs and 28 narrow-line radio galaxies. Redshift information is available for 96 per cent of these. Thus our selection technique is ~90 per cent efficient at finding radio-loud quasars and BL Lacs. Reaching 5-GHz radio fluxes ~50mJy and 0.1-2.0keV X-ray fluxes a few W10-14erg/cm^2^/s, DXRBS is the faintest and largest flat-spectrum radio sample with nearly complete (~85 per cent) identification.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/1763
- Title:
- Detectability of radio emission from exoplanets
- Short Name:
- J/MNRAS/478/1763
- Date:
- 19 Jan 2022 00:23:37
- Publisher:
- CDS
- Description:
- Like the magnetized planets in our Solar system, magnetized exoplanets should emit strongly at radio wavelengths. Radio emission directly traces the planetary magnetic fields and radio detections can place constraints on the physical parameters of these features. Large comparative studies of predicted radio emission characteristics for the known population of exoplanets help to identify what physical parameters could be the key for producing bright, observable radio emission. Since the last comparative study, many thousands of exoplanets have been discovered. We report new estimates for the radio flux densities and maximum emission frequencies for the current population of known exoplanets orbiting pre-main-sequence and main-sequence stars with spectral types F-M. The set of exoplanets predicted to produce observable radio emission are Hot Jupiters orbiting young stars. The youth of these systems predicts strong stellar magnetic fields and/or dense winds, which are the key for producing bright, observable radio emission. We use a new all-sky circular polarization Murchison Widefield Array survey to place sensitive limits on 200MHz emission from exoplanets, with 3{sigma} values ranging from 4.0 to 45.0mJy. Using a targeted Giant Metrewave Radio Telescope observing campaign, we also report a 3{sigma} upper limit of 4.5mJy on the radio emission from V830 Tau b, the first Hot Jupiter to be discovered orbiting a pre-main-sequence star. Our limit is the first to be reported for the low-frequency radio emission from this source.
- ID:
- ivo://CDS.VizieR/J/MNRAS/329/227
- Title:
- 2dF Galaxy Redshift Survey. II.
- Short Name:
- J/MNRAS/329/227
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have cross-matched the 1.4-GHz NRAO VLA Sky Survey (NVSS, Condon 1998, Cat. <VIII/65>) with the first 210 fields observed in the 2dF Galaxy Redshift Survey (2dFGRS, Colless, 2001, Cat. <VII/226>), covering an effective area of 325{deg}^2^ (about 20 per cent of the final 2dFGRS area). This yields a set of optical spectra of 912 candidate NVSS counterparts, of which we identify 757 as genuine radio identifications - the largest and most homogeneous set of radio source spectra ever obtained. The 2dFGRS radio sources span the redshift range z=0.005 to 0.438, and are a mixture of active galaxies (60 per cent) and star-forming galaxies (40 per cent). About 25 per cent of the 2dFGRS radio sources are spatially resolved by NVSS, and the sample includes three giant radio galaxies with projected linear size greater than 1 Mpc. The high quality of the 2dF spectra means we can usually distinguish unambiguously between AGN and star-forming galaxies. We make a new determination of the local radio luminosity function at 1.4 GHz for both active and star-forming galaxies, and derive a local star formation density of 0.022+/-0.004M_{sun}_/yr/Mpc^3^ (H_0_=50km/s/Mpc)
- ID:
- ivo://CDS.VizieR/J/ApJ/689/194
- Title:
- Distances of galactic planetary nebulae
- Short Name:
- J/ApJ/689/194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galactic planetary nebula (PN) distances are derived, except in a small number of cases, through the calibration of statistical properties of PNs. Such calibrations are limited by the accuracy of individual PN distances, which are obtained with several nonhomogeneous methods, each carrying its own set of liabilities. In this paper we use the physical properties of the PNs in the Magellanic Clouds and their accurately known distances to recalibrate the Shklovsky/Daub (1982ApJ...260..612D) distance technique. Our new calibration is very similar (within 1%) to the commonly used distance scale by Cahn et al. (1992, Cat. J/A+AS/94/399), although there are important differences. We present a catalog of Galactic PN distances using our recalibration, which can be used for future applications, and compare the best individual Galactic PN distances to our new and several other distance scales, both in the literature and newly recalibrated by us, finding that our scale is the most reliable to date.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/2985
- Title:
- Double-lobed radio sources catalog
- Short Name:
- J/MNRAS/446/2985
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Current wide-area radio surveys are dominated by active galactic nuclei, yet many of these sources have no identified optical counterparts. Here we investigate whether one can constrain the nature and properties of these sources, using Fanaroff-Riley type II (FR II) radio galaxies as probes. These sources are easy to identify since the angular separation of their lobes remains almost constant at some tens of arcseconds for z>1. Using a simple algorithm applied to the Faint Images of the Radio Sky at Twenty-cm survey, we obtain the largest FR II sample to date, containing over 104 double-lobed sources. A subset of 459 sources is matched to Sloan Digital Sky Survey quasars. This sample yields a statistically meaningful description of the fraction of quasars with lobes as a function of redshift and luminosity. This relation is combined with the bolometric quasar luminosity function and a disc-lobe correlation to obtain a robust prediction for the density of FR IIs on the radio sky. We find that the observed density can be explained by the population of known quasars, implying that the majority of powerful jets originate from a radiatively efficient accretion flow with a linear jet-disc coupling. Finally, we show that high-redshift jets are more often quenched within 100kpc, suggesting a higher efficiency of jet-induced feedback into their host galaxies.
- ID:
- ivo://CDS.VizieR/VIII/55
- Title:
- DRAO Penticton P-survey Database
- Short Name:
- VIII/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains 1692 radio sources observed with the Penticton synthesis telescope at 408 MHz and at 1420 MHz. The catalog is comprised of sources detected in the P-surveys 1P through 9P, 12P through 15P, and 20P through 27P (see the "References" section below). The database was provided by R.Roger & C.R.Purton in May 1990 and an update of the data with further P-surveys is currently in progress.
- ID:
- ivo://CDS.VizieR/J/ApJ/818/182
- Title:
- Early-type galaxies at z<0.04 star formation rates
- Short Name:
- J/ApJ/818/182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We address the relation between star formation and active galactic nucleus (AGN) activity in a sample of 231 nearby (0.0002<z<0.0358) early-type galaxies by carrying out a multi-wavelength study using archival observations in the UV, IR, and radio. Our results indicate that early-type galaxies in the current epoch are rarely powerful AGNs, with P<10^22^W/Hz for a majority of the galaxies. Only massive galaxies are capable of hosting powerful radio sources while less massive galaxies are hosts to lower radio power sources. Evidence of ongoing star formation is seen in approximately 7% of the sample. The star formation rate (SFR) of these galaxies is less than 0.1M_{sun}_/yr. They also tend to be radio faint (P<10^22^W/Hz). There is a nearly equal fraction of star-forming galaxies in radio faint (P<10^22^W/Hz) and radio bright galaxies (P>=10^22^W/Hz) suggesting that both star formation and radio mode feedback are constrained to be very low in our sample. We notice that our galaxy sample and the Brightest Cluster Galaxies follow similar trends in radio power versus SFR. This may be produced if both radio power and SFR are related to stellar mass.
- ID:
- ivo://CDS.VizieR/J/MNRAS/436/3759
- Title:
- ECDFS sources optical/IR counterparts
- Short Name:
- J/MNRAS/436/3759
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The sub-mJy radio population is a mixture of active systems, that is star-forming galaxies (SFGs) and active galactic nuclei (AGNs). We study a sample of 883 radio sources detected at 1.4GHz in a deep Very Large Array survey of the Extended Chandra Deep Field-South that reaches a best rms sensitivity of 6{mu}Jy. We have used a simple scheme to disentangle SFGs, radio-quiet (RQ), and radio-loud (RL) AGNs based on the combination of radio data with Chandra X-ray data and mid-infrared observations from Spitzer. We find that at flux densities between about 30 and 100{mu}Jy, the radio population is dominated by SFGs (~60%) and that RQ AGNs become increasingly important over RL ones below 100 {mu}Jy. We also compare the host galaxy properties of the three classes in terms of morphology, optical colours and stellar masses. Our results show that both SFG and RQ AGN host galaxies have blue colours and late-type morphology while RL AGNs tend to be hosted by massive red galaxies with early-type morphology. This supports the hypothesis that radio emission in SFGs and RQ AGNs mainly comes from the same physical process: star formation in the host galaxy.
