Related papers: Radio-loudness along the quasar main sequence
We have studied the dependence of the AGN nuclear radio (1.4 GHz) luminosity on both the AGN 2-10 keV X-ray and the host-galaxy K-band luminosity. A complete sample of 1268 X-ray selected AGN (both type 1 and type 2) has been used, which is…
The radio emission in radio loud quasars originates in a jet carrying relativistic electrons. In radio quiet quasars (RQQs) the relative radio emission is ~10^3 times weaker, and its origin is not established yet. We show here that there is…
(Abridged) We present the results from new 15 ks Chandra-ACIS and 4.9 GHz Very Large Array observations of 13 galaxies hosting low luminosity AGN. This completes the multiwavelength study of a sample of 51 nearby early-type galaxies…
Radio-bright, jetted quasars at $z>5$ serve as unique laboratories for studying supermassive black hole activity in the early Universe. In this work, we present a sample of high-$z$ jetted quasars selected from the combination of the radio…
We study a complete and distance-limited sample of 25 LINERs, 21 of which have been imaged with the Hubble Space Telescope to study their physical properties and to compare their radio and optical properties with those of other samples of…
We use restframe near- and mid-IR data of an isotropically selected sample of quasars and radio galaxies at 1.0 \leq z \leq 1.4, which have been published previously, to study the wavelength-dependent anisotropy of the IR emission. For that…
We present the results of Chandra ACIS-S snapshot observations of six radio-loud quasars (RLQs) at z=3.5-4.7. These observations sample luminous RLQs with moderate-to-high radio-loudness (R=200-9600) and aim to connect the X-ray properties…
We study the differences in physical properties of quasar-host galaxies using an optically selected sample of radio loud (RL) and radio quiet (RQ) quasars (in the redshift range 0.15 < z < 1.9) which we have further cross-matched with the…
Submillimeter (and in some cases millimeter) wavelength continuum measurements are presented for a sample of 40 active galactic nuclei (probably all quasars) lensed by foreground galaxies. The object of this study is to use the lensing…
We investigate the evolution of both the radio-loud fraction (RLF) and (using stacking analysis) the mean radio-loudness of quasars. We consider how these values evolve as a function of redshift and luminosity, black hole (BH) mass and…
We tested the effectiveness of radio selection to discover heavily obscured AGNs, particularly at high-z, and we measured their abundance for the first time from a radio perspective. We consider the radio sources detected in the J1030…
We study the environmental properties of z<1.2 radio-selected AGN belonging to the ~2 square degrees of the COSMOS field, finding that about 20% of them appear within overdense structures. AGN with $P[1.4 GHz]>10^{23.5} W Hz^{-1} sr^{-1}$…
Remnant radio galaxies represent the dying phase of radio-loud active galactic nuclei (AGN). Large samples of remnant radio galaxies are important for quantifying the radio galaxy life cycle. The remnants of radio-loud AGN can be identified…
Context. Active galactic nuclei (AGNs) and star forming galaxies (SFGs) are the primary sources of extragalactic radio sky. But it is difficult to distinguish the radio emission produced by AGNs from that by SFGs, especially when the radio…
It is now established that the faint radio population is a mixture of star-forming galaxies and faint active galactic nuclei (AGNs), with the former dominating below S(1.4GHz) \sim 100 muJy and the latter at larger flux densities. The faint…
For nearly seven decades astronomers have been studying active galaxies, that is to say galaxies with actively accreting central supermassive black holes, AGN. A small fraction of these are characterized by luminous, powerful radio…
A cross-correlation of the SDSS DR7 with the FIRST radio survey makes it possible to conduct a joined multiwavelength statistical study of radio-optical galaxy properties on a very large number of sources. Our goal is to improve the study…
We present the radio properties of optically selected quasars with $z\geq3$. The complete sample consists of 102 quasars with a flux density level $S_{1.4}\geq100$ mJy in a declination range -35$^{\circ}$ $\leq$ Dec $\leq$ +49$^{\circ}$.…
In order to understand the role of radio-quiet quasars (RQQs) in galaxy evolution, we must determine the relative levels of accretion and star-formation activity within these objects. Previous work at low radio flux-densities has shown that…
Based on the miscellaneous published radio and optical data, SDSS and APM catalogue we consider the various properties of the giant radio sources (gRS) with the aim of refining the conditions leading to the formation of these objects. We…