- ID:
- ivo://CDS.VizieR/J/AJ/141/182
- Title:
- Radio and optical properties of QSOs
- Short Name:
- J/AJ/141/182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the largest homogeneous quasar sample with high-quality optical spectra and robust radio morphology classifications assembled to date, we investigate relationships between radio and optical properties with unprecedented statistical power. The sample consists of 4714 radio quasars from FIRST with S_20_>=2mJy and with spectra from the Sloan Digital Sky Survey (SDSS). Radio morphology classes include core-only (core), core-lobe (lobe), core-jet (jet), lobe-core-lobe (triple), and double-lobe.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/381/211
- Title:
- Radio galaxies in the 2SLAQ LRG Survey
- Short Name:
- J/MNRAS/381/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have combined optical data from the 2dF-SDSS (Sloan Digital Sky Survey) LRG (Luminous Red Galaxy) and QSO (quasi-stellar object) (2SLAQ) redshift survey with radio measurements from the 1.4GHz VLA (Very Large Array) FIRST (Faint Images of the Radio Sky at Twenty-cm) and NVSS (NRAO VLA Sky Survey) surveys to identify a volume-limited sample of 391 radio galaxies at redshift 0.4<z<0.7. By determining an accurate radio luminosity function for luminous early-type galaxies in this redshift range, we can investigate the cosmic evolution of the radio-galaxy population over a wide range in radio luminosity.
- ID:
- ivo://CDS.VizieR/J/ApJS/91/507
- Title:
- Radio-galaxies surface photometry
- Short Name:
- J/ApJS/91/507
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results on the optical morphology and structure of 25 low-luminosity radio galaxies. The radial dependence of parameters like the surface brightness, ellipticity, center, and position angle of the isophotes is presented to study the properties of the galaxies. Results for individual objects are discussed.
- ID:
- ivo://CDS.VizieR/J/ApJS/179/306
- Title:
- Radio galaxy morphologies
- Short Name:
- J/ApJS/179/306
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a statistical study of 51 radio galaxies at the millijansky flux level selected from the Faint Images of the Radio Sky at Twenty cm survey, including their optical morphologies and structure obtained with the Hubble Space Telescope (HST). Our optical imaging is significantly deeper (~2mag) than previous studies with the superior angular resolution of space-based imaging. We that find 8/51 (16%) of the radio sources have no optically identifiable counterpart to AB~24mag. For the remaining 43 sources, only 25 are sufficiently resolved in the HST images to reliably assign a visual classification: 15 (60%) are elliptical galaxies, two (8%) are late-type spiral galaxies, one (4%) is an S0, three (12%) are pointlike objects (quasars), and four (16%) are merger systems. We find a similar distribution of optical types with measurements of the Sersic index.
- ID:
- ivo://CDS.VizieR/J/MNRAS/460/3202
- Title:
- Radio-loud AGN with relativistic jets
- Short Name:
- J/MNRAS/460/3202
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep near-infrared (NIR) images of a sample of 19 intermediate-redshift (0.3<z<1.0) radio-loud active galactic nuclei (AGN) with powerful relativistic jets (L_1.4GHz_>10^27^W/Hz), previously classified as flat-spectrum radio quasars. We also compile host galaxy and nuclear magnitudes for blazars from literature. The combined sample (this work and compilation) contains 100 radio-loud AGN with host galaxy detections and a broad range of radio luminosities L_1.4GHz_~10^23.7^-10^28.3^W/Hz, allowing us to divide our sample into high-luminosity blazars (HLBs) and low-luminosity blazars (LLBs). The host galaxies of our sample are bright and seem to follow the {mu}_e_-Reff relation for ellipticals and bulges. The two populations of blazars show different behaviours in the M_K,nuclear_-M_K,bulge_ plane, where a statistically significant correlation is observed for HLBs. Although it may be affected by selection effects, this correlation suggests a close coupling between the accretion mode of the central supermassive black hole and its host galaxy, which could be interpreted in terms of AGN feedback. Our findings are consistent with semi-analytical models where low-luminosity AGN emit the bulk of their energy in the form of radio jets, producing a strong feedback mechanism, and high-luminosity AGN are affected by galaxy mergers and interactions, which provide a common supply of cold gas to feed both nuclear activity and star formation episodes.
- ID:
- ivo://CDS.VizieR/J/MNRAS/461/2346
- Title:
- Radio-loud and radio-quiet quasars sample
- Short Name:
- J/MNRAS/461/2346
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare covering factors of circumnuclear dusty obscurers in radio-loud and radio-quiet quasars. The radio-loud quasars are represented by a sample of FR II quasars obtained by cross-matching a catalog of the FR II radio sources selected by van Velzen et al. with the SDSS DR7 catalog of quasars. Covering factors of FR II quasars are compared with covering factors of the radio-quiet quasars matched with them in redshift, black hole mass, and Eddington-ratio. We found that covering factors, proxied by the infrared-to-bolometric luminosity ratio, are on average slightly smaller in FR II quasars than in radio-quiet quasars, however, this difference is statistically significant only for the highest Eddington ratios. For both samples, no statistically significant dependence of a median covering factor on Eddington ratio, black hole mass, nor redshift can be claimed.
5467. Radio-loud QSOs at z~4
- ID:
- ivo://CDS.VizieR/J/MNRAS/348/857
- Title:
- Radio-loud QSOs at z~4
- Short Name:
- J/MNRAS/348/857
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained spectra of 60 red, star-like objects (m_E_<18.8) identified with FIRST radio sources, S_1.4GHz_>1mJy. Eight are quasi-stellar objects (QSOs) with redshift z>3.6. Combined with our earlier pilot search, our sample of 121 candidates yields a total of 18 z>3.6 QSOs (10 of these with z>4.0). 8 per cent of candidates with S_1.4GHz_<10mJy and 37 per cent of candidates with S_1.4GHz_>10mJy are QSOs with z>3.6. The surface density of m_E_<18.8, S_1.4GHz_>1mJy, z>4 QSOs is 0.003deg^-2^. This is currently the only well-defined sample of radio-loud QSOs at z~4 selected independently of radio spectral index. The QSOs are highly luminous in the optical (eight have M_B_<28, q_0_=0.5, H_0_=50km/s/Mpc). The SEDs are as varied as those seen in optical searches for high-redshift QSOs, but the fraction of objects with weak (strongly self-absorbed) Ly emission is marginally higher (3 out of 18) than for high-redshift QSOs from SDSS (5 out of 96).
- ID:
- ivo://CDS.VizieR/J/MNRAS/390/289
- Title:
- Radio observations of A3158
- Short Name:
- J/MNRAS/390/289
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 1.4- and 2.5-GHz Australia Telescope Compact Array (ATCA) observations of the galaxy cluster A3158 (z=0.0597) which is located within the central part of the Horologium-Reticulum supercluster (HRS). Spectroscopic data for the central part of the HRS suggest that A3158 is in a dynamically important position within the supercluster and that it is moving toward the double cluster system A3125/A3128 which marks the centre of the HRS. A total of 110 radio galaxies are detected in a 35-arcmin radius about the cluster at 1.4GHz, of which 30 are also detected at 2.5GHz.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1358
- Title:
- Radio observations of the HDFS region. I
- Short Name:
- J/AJ/130/1358
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is the first of a series describing the results of the Australia Telescope Hubble Deep Field-South radio survey. The survey was conducted at four wavelengths, 20, 11, 6, and 3cm, over a 4 year period and achieves an rms sensitivity of about 10{mu}Jy at each wavelength. We describe the observations and data reduction processes and present data on radio sources close to the center of the Hubble Deep Field-South. We discuss in detail the properties of a subset of these sources. The sources include both starburst galaxies and galaxies powered by an active galactic nucleus and range in redshift from 0.1 to 2.2. Some of them are characterized by unusually high radio-to-optical luminosities, presumably caused by dust extinction.
- ID:
- ivo://CDS.VizieR/J/AJ/135/2470
- Title:
- Radio observations of the HDFS region. IV.
- Short Name:
- J/AJ/135/2470
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Australia Telescope Hubble Deep Field-South (ATHDF-S) survey of the Hubble Deep Field-South (HDF-S) reaches sensitivities of ~10uJy at 1.4, 2.5, 5.2, and 8.7GHz, making the ATHDF-S one of the deepest surveys ever performed with the Australia Telescope Compact Array (ATCA). Here, we present the optical identifications of the ATHDF-S radio sources using data from the literature. We find that ~66% of the radio sources have optical counterparts to I=23.5mag. Deep Hubble Space Telescope (HST) imaging of the area identifies a further 12% of radio sources. We present new spectroscopic observations for 98 of the radio sources and supplement these spectroscopic redshifts with photometric ones calculated from five-band optical imaging.
