- ID:
- ivo://CDS.VizieR/J/ApJ/886/48
- Title:
- Radio & opt/NIR counterparts of S2COSMOS submm galaxies
- Short Name:
- J/ApJ/886/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify multi-wavelength counterparts to 1147 submillimeter sources from the S2COSMOS SCUBA-2 survey of the COSMOS field by employing a recently developed radio+machine-learning method trained on a large sample of Atacama Large Millimeter/submillimeter Array (ALMA)-identified submillimeter galaxies (SMGs), including 260 SMGs identified in the AS2COSMOS pilot survey. In total, we identify 1222 optical/near-infrared (NIR)/radio counterparts to the 897 S2COSMOS submillimeter sources with S_850_>1.6mJy, yielding an overall identification rate of (78+/-9)%. We find that (22+/-5)% of S2COSMOS sources have multiple identified counterparts. We estimate that roughly 27% of these multiple counterparts within the same SCUBA-2 error circles very likely arise from physically associated galaxies rather than line-of-sight projections by chance. The photometric redshift of our radio+machine-learning-identified SMGs ranges from z=0.2 to 5.7 and peaks at z=2.3+/-0.1. The AGN fraction of our sample is (19+/-4)%, which is consistent with that of ALMA SMGs in the literature. Comparing with radio/NIR-detected field galaxy population in the COSMOS field, our radio+machine-learning-identified counterparts of SMGs have the highest star formation rates and stellar masses. These characteristics suggest that our identified counterparts of S2COSMOS sources are a representative sample of SMGs at z<~3. We employ our machine-learning technique to the whole COSMOS field and identified 6877 potential SMGs, most of which are expected to have submillimeter emission fainter than the confusion limit of our S2COSMOS surveys (S_850um_<~1.5mJy). We study the clustering properties of SMGs based on this statistically large sample, finding that they reside in high-mass dark matter halos ((1.2+/-0.3)x10^13^h^-1^M_{sun}_), which suggests that SMGs may be the progenitors of massive ellipticals we see in the local universe.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/555/A4
- Title:
- Radio polarimetry of CSS sources
- Short Name:
- J/A+A/555/A4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multi-frequency VLA polarisation observations of compact steep spectrum (CSS) sources. About half of the sources are point-like even at the resolution of about 0.1x0.1 arcseconds. The remaining sources have double or triple structure. Low values for the percentage of polarised emission in CSS sources is confirmed. On the average, quasars are more polarised than galaxies. A wide range of RM values have been measured. There are clear indications of very large RMs up to about 5585rad/m^2^. CSS galaxies are characterized by RM values that are larger than CSS quasars. The majority of the objects show very large values of RM.
- ID:
- ivo://CDS.VizieR/J/ApJ/448/521
- Title:
- Radio powers in radio galaxies
- Short Name:
- J/ApJ/448/521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We know from previous work that there are substantial differences between powerful FR I and FR II radio galaxies. In this paper we look at the correlations of line luminosity, radio luminosity, core radio power, and host galaxy optical magnitude independently for FR I and FR II radio galaxies and compare these correlations with those for an optically selected control sample of early-type galaxies. In this, Paper I in a two-paper series, we list the principal results.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/1201
- Title:
- Radio properties of brightest cluster galaxies
- Short Name:
- J/MNRAS/453/1201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the radio properties of the brightest cluster galaxies (BCGs) in a large sample of X-ray selected galaxy clusters comprising the Brightest Cluster Sample (BCS), the extended BCS and ROSAT-ESO Flux Limited X-ray cluster catalogues. We have multifrequency radio observations of the BCG using a variety of data from the Australia Telescope Compact Array, Jansky Very Large Array and Very Long Baseline Array telescopes. The radio spectral energy distributions of these objects are decomposed into a component attributed to on-going accretion by the active galactic nuclei (AGN) that we refer to as 'the core', and a more diffuse, ageing component we refer to as the 'non-core'. These BCGs are matched to previous studies to determine whether they exhibit emission lines (principally H{alpha}), indicative of the presence of a strong cooling cluster core. We consider how the radio properties of the BCGs vary with cluster environmental factors. Line emitting BCGs are shown to generally host more powerful radio sources, exhibiting the presence of a strong, distinguishable core component in about 60 per cent of cases. This core component more strongly correlates with the BCG's [OIII] 5007{AA} line emission. For BCGs in line emitting clusters, the X-ray cavity power correlates with both the extended and core radio emission, suggestive of steady fuelling of the AGN over bubble-rise time-scales in these clusters.
- 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/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.
- 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.
- 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.
- 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.
- 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.
