Related papers: Dark bubbles around high-redshift radio-loud AGN
We present a new sample of 35 quasars selected from the FIRST radio survey and the Deeprange I-band survey (Postman et al. 1998, 2002). A comparison with the FIRST Bright Quasar survey samples reveals that this I-band selected sample is…
The most elusive and extreme sub-class of active galactic nuclei (AGNs), known as BL Lac objects, shows features that can only be explained as the result of relativistic effects occurring in jets pointing at a small angle with respect to…
The appearance of active galactic nuclei (AGN) depends so strongly on orientation that our current classification schemes are dominated by random pointing directions instead of more interesting physical properties. Light from the centers of…
We have identified a population of blank field sources (or `blanks') among the ROSAT bright unidentified X-ray sources with faint optical counterparts. The extreme X-ray over optical flux ratio of blanks is not compatible with the main…
We present observations at 1.1 mm towards 16 powerful radio galaxies and a radio-quiet quasar at 0.5<z<6.3 acquired with the AzTEC camera mounted at the JCMT and ASTE to study the spatial distribution of submillimeter galaxies towards…
We use a physically motivated semi-analytic model, based on the mass function of dark matter halos, to predict the number of radio-loud quasars as a function of redshift and luminosity. Simple models in which the central BH mass scales with…
The radio quasar luminosity function exhibits an upturn around $L_{6\rm\:GHz}=10^{23}$ W Hz$^{-1}$ that is well-modelled by a star-forming host galaxy population. This distribution leads some authors to cite star formation as the main radio…
In the decreasing intrinsic redshift (DIR) model galaxies are assumed to be born as compact objects that have been ejected with large intrinsic redshift components, z_(i), out of the nuclei of mature AGN galaxies. As young AGN (quasars)…
Narrow-line Seyfert 1 galaxies (NLS1s) are active galactic nuclei (AGN) recently identified as a new class of $\gamma$-ray sources. The high energy emission is explained by the presence of a relativistic jet observed at small angles, just…
We present the discovery of PSO J030947.49+271757.31, the radio brightest (23.7 mJy at 1.4 GHz) active galactic nucleus (AGN) at z>6.0. It was selected by cross-matching the NRAO VLA Sky Survey and the Panoramic Survey Telescope and Rapid…
The broad absorption line (BAL) features seen in a small fraction of quasar optical/UV spectra are attributed to bulk outflows away from the quasar core. Observational evidence suggests that dust plays a key role in these systems, although…
When a gravitational lens produces two or more images of a quasar's radio jet the images can be compared to reveal the presence of small structures along one or more of the lines of sight. If mass is distributed smoothly on scales of <~…
Being dominated by non-thermal emission from aligned relativistic jets, blazars allow us to elucidate the physics of extragalactic jets, and, ultimately, how energy is extracted from the central black hole. Crucial information about jet…
Several studies support the existence of a link between the AGN and star formation activity. Radio jets have been argued to be an ideal mechanism for direct interaction between the AGN and the host galaxy. A drawback of previous surveys of…
We report observations of the low-luminosity z = 5.50 quasar RD J030117+002025 (RD0301 hereafter) at 250 GHz (1.20mm) using the Max-Planck Millimeter Bolometer (MAMBO) array at the IRAM 30-meter telescope. The quasar was detected with a…
The shape of bent, double-lobed radio sources requires a dense gaseous medium. Bent sources can therefore be used to identify galaxy clusters and characterize their evolutionary history. By combining radio observations from the Very Large…
We report 250 GHz (1.2mm) observations of redshift > 3.8 quasars from the Palomar Sky Survey (PSS) sample, using the Max-Planck Millimetre Bolometer (MAMBO) array at the IRAM 30-metre telescope. Eighteen sources were detected and upper…
I summarize Xray properties of high redshift radio galaxies, beginning with a brief review of what has been learned from Xray observations of low redshift powerful radio galaxies (in particular, Cygnus A), and then turning to Chandra…
The radio-loud AGN unification model associates powerful radio galaxies with radio-loud quasars and blazars. In analogy with the radio-quiet scheme, the nuclear regions of objects showing only narrow emission lines in their optical spectrum…
The ubiquity of Lyman alpha (Ly$\alpha$) emission in a sample of four bright [O III]-strong star-forming galaxies with redshifts above 7 has led to the suggestion that such luminous sources represent a distinct population compared to their…