- ID:
- ivo://CDS.VizieR/J/MNRAS/383/479
- Title:
- Radio obs. of optically obscured galaxies
- Short Name:
- J/MNRAS/383/479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper analyses the radio properties of a subsample of optically obscured (R>=25.5) galaxies observed at 24um by the Spitzer Space Telescope within the First Look Survey. Ninety-six F24um>=0.35mJy objects out of 510 are found to have a radio counterpart at 1.4GHz, 610MHz or at both frequencies, respectively, down to ~40 and ~200uJy. IRAC photometry sets the majority of them in the redshift interval z~=[1-3] and allows for a broad distinction between active galactic nucleus (AGN) dominated galaxies (~47 per cent of the radio-identified sample) and systems powered by intense star formation (~13 per cent), the remaining objects being impossible to classify. The percentage of radio identifications is a strong function of 24-um flux: almost all sources brighter than F_24um_~2mJy are endowed with a radio flux at both 1.4GHz and 610MHz, while this fraction drastically decreases by lowering the 24-um flux level.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/167/103
- Title:
- Radio/Optical catalog of the SSA 13 field
- Short Name:
- J/ApJS/167/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a 1.4GHz catalog of 810 radio sources (560 sources in the complete sample) found in the SSA 13 field (RA=13:12, DE=42:38). The 1.4GHz radio image was obtained from a 91hr VLA integration with an rms noise level of 4.82uJy/beam at the field center. Optical images in the R band (6300{AA}) and z band (9200{AA}) with 3{sigma} detection magnitudes of 26.1 and 24.9, respectively, were obtained from three observing nights on the 8m Subaru Telescope. We find that 88%+/-2% of the radio sources are identified with an optical counterpart.
- ID:
- ivo://CDS.VizieR/J/AJ/124/1418
- Title:
- Radio-optical identification of star clusters
- Short Name:
- J/AJ/124/1418
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A reexamination of the correspondence between 6cm radio continuum sources and young star clusters in the Antennae galaxies indicates that ~85% of the strong thermal sources have optical counterparts, once the optical image is shifted 1.2" to the southwest. A sample of 37 radio-optical matches are studied in detail, showing correlations between radio properties (i.e., total flux and spectral index) and a variety of optical characteristics (i.e., intrinsic cluster brightness, H{alpha} flux and equivalent width, extinction, and cluster ages). There is a strong correlation between the radio flux and the intrinsic optical brightness.
- ID:
- ivo://CDS.VizieR/J/MNRAS/276/614
- Title:
- Radio-optical 151MHz survey of the N. Ecl. Cap
- Short Name:
- J/MNRAS/276/614
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Cambridge Low Frequency Synthesis Telescope has been used to survey a region ~7x7deg^2^ about the North Ecliptic Cap at 151MHz with a resolution of 70x77arcsec^2^. The resulting radio source catalogue of 400 sources is complete to a peak flux density limit of 120mJy/beam. Using the Cambridge APM we have searched for identifications on the Palomar Sky Survey plate 550 which covers much of the survey area, and we list the 157 sources with one or more optical objects within 15arcsec of the radio position.
- ID:
- ivo://CDS.VizieR/J/ApJ/666/201
- Title:
- Radio polarimetry of the ELAIS N1 field
- Short Name:
- J/ApJ/666/201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep polarimetric observations at 1420MHz of the European Large Area ISO Survey North 1 region (ELAIS N1) as part of the Dominion Radio Astrophysical Observatory Planck Deep Fields project. By combining closely spaced aperture synthesis fields, we image a region of 7.43deg^2^ to a maximum sensitivity in Stokes Q and U of 78uJy/beam, and detect 786 compact sources in Stokes I. Of these, 83 exhibit polarized emission.
- ID:
- ivo://CDS.VizieR/J/MNRAS/401/1388
- Title:
- Radio polarization of WMAP point sources
- Short Name:
- J/MNRAS/401/1388
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations were conducted using the VLA in D-configuration between 01.40 and 19.30 UT on 2008 August 1.
- ID:
- ivo://CDS.VizieR/J/AJ/102/1663
- Title:
- Radio properties of extragal. IRAS sources
- Short Name:
- J/AJ/102/1663
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog presents radio and optical identifications of extragalactic IRAS sources from the IRAS Faint Source Catalog |b| > 50{deg} (Moshir et al., 1989 Cat. <II/156>). Sources with flux density > 0.2 at 60 microns and with S_60_ > S_12_ were identified by position coincidence with radio sources stronger than 25 mJy and lying north of declination = 5{deg} on the Green Bank 4.85 GHz sky map. Published VLA maps, new 4.86 GHz VLA maps made with 15 arcsec resolution, and accurate optical positions were used to confirm 122 candidate identifications. This catalog contains a merged version of tables 1 and 2 from the paper.
- ID:
- ivo://CDS.VizieR/J/ApJ/445/62
- Title:
- Radio properties of optically selected quasars
- Short Name:
- J/ApJ/445/62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Approximately one-quarter (256 objects) of the Large Bright Quasar Survey (LBQS, Hewett et al., 1995, Cat. <J/AJ/109/1498>) has been observed with the VLA at 8.4GHz, resulting in 44 detections (17%) with a median 3{sigma} noise limit of 0.29mJy. Quasars with radio luminosity detectable at this limit are under-represented at faint absolute blue magnitudes (M_B_>=-24), an effect which cannot be explained by a potential LBQS selection bias against quasars which have large radio luminosities and small optical luminosities. The radio-loud (8GHz luminosity >10^25^W/Hz) fraction is observed to change as a function of redshift and MB, for M_B_<-24, although the causal variable is ambiguous. The description most consistent with the available data is that radio-loud fraction is approximately constant over the range -27.5<M_B_<-24 and increases at brighter absolute magnitudes. The radio-loud fraction as a function of redshift reaches a local maximum at z~1, and, aside from the effects of increased radio-loud fraction at bright M_B_, remains roughly constant to redshifts approaching 5. The log R_8.4_ distribution (radio-to-optical luminosity ratio) of the current LBQS sample may be bimodal, but the results of statistical tests are ambiguous, requiring a larger sample size to become definite.
- ID:
- ivo://CDS.VizieR/J/other/PPMtO/17B.1
- Title:
- Radio properties of ROSAT sources
- Short Name:
- J/other/PPMtO/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A cross-identification of the southern-sky objects with the ROSAT All-Sky Survey (Cat. <IX/10>) and Parkes-MIT-NRAO (PMN) Radio (5GHz) Survey (Cat. <VIII/38>) yields a list of 642 sources. Subsequential optical identification for all these coincidences has been taken to form a large sample of galaxies and Active Galactic Nuclei (AGNs). As a result, 311 (52%) were previously optically identified as extragalactic objects. The fluxes detected from X-ray, optical, and radio bands for them are compiled. This database allows an investigation on broad band energy distribution and other possible correlations among spectral indices and luminosities for various types of extragalactic objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/900/125
- Title:
- Radio properties of Swift/BAT AGNs
- Short Name:
- J/ApJ/900/125
- Date:
- 02 Feb 2022 09:04:43
- Publisher:
- CDS
- Description:
- We address the very large diversity of jet production efficiency in active galactic nuclei (AGNs) by using data on low-redshift AGNs selected from the Swift/BAT catalog and having black hole (BH) masses larger than 10^8.5^M_{sun}_. Most of these AGNs accrete at intermediate rates and have bolometric luminosities dominated by mid-IR radiation. Our sample contains 14% radio-loud (RL), 6% radio-intermediate, and 80% radio-quiet (RQ) AGNs. All RL objects are found to have extended radio structures, and most of them have classical FR II morphology. Converting their radio loudness to jet production efficiency, we find that the median of this efficiency is on the order of ({epsilon}_d_/0.1)%, where {epsilon}_d_=L_bol_/(dM/dt)c^2^ is the radiation efficiency of the accretion disk. Without knowing the contribution of jets to the radio emission in RQ AGNs, we are only able to estimate their efficiencies using upper limits. Their median is found to be 0.002({epsilon}_d_/0.1)%. Our results suggest that some threshold conditions must be satisfied to allow the production of strong, relativistic jets in RL AGNs. We discuss several possible scenarios and argue that the production of collimated, relativistic jets must involve the Blandford-Znajek mechanism and can be activated only in those AGNs whose lifetime is longer than the time required to enter the magnetically arrested disk (MAD). Presuming that MAD is required to collimate relativistic jets, we expect that the weak nonrelativistic jets observed in some RQ AGNs are produced by accretion disks rather than by rotating BHs.
