相关论文: Evidence for radio loud to radio quiet evolution f…

Red quasi-stellar objects (QSOs) are a subset of the luminous end of the cosmic population of active galactic nuclei (AGN), most of which are reddened by intervening dust along the line-of-sight towards their central engines. In recent work…

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…

A picture has emerged connecting QSOs with Sub-Millimetre Galaxies (SMGs) through an evolutionary sequence in which forming galaxies are initially FIR-luminous but X-ray weak, similar to known SMGs. As the black hole and spheroid grow with…

We study the growth of black holes and stellar population in spheroids at high redshift using several (sub)mm-loud QSO samples. Applying the same criteria established in an earlier work, we find that, similar to IR QSOs at low redshift, the…

Red quasi-stellar objects (QSOs) are a subset of the quasar population with colours consistent with reddening due to intervening dust. Recent work has demonstrated that red QSOs show special radio properties that fundamentally distinguish…

We calculate simultaneously the radio and optical luminosity evolutions of quasars, and the distribution in radio loudness R defined as the ratio of radio and optical luminosities, using a flux limited data set containing 636 quasars with…

A minority of the optically selected quasar population are red at optical wavelengths due to the presence of dust along the line-of-sight. A key focus of many red quasar studies is to understand their relationship with the overall quasar…

We determine the radio and optical luminosity evolutions and the true distribution of the radio loudness parameter R, defined as the ratio of the radio to optical luminosity, for a set of more than 5000 quasars combining SDSS optical and…

We present a detailed analysis of a sample of radio-detected quasars, obtained by matching together objects from the FIRST and 2dF Quasar Redshift Surveys. The dataset consists of 113 sources, spanning a redshift range 0.3 < z < 2.2, with…

The evolution of QSO clustering is investigated with a new sample of 388 QSOs with 0.3<z<2.2, B<20.5 and M_B<-23. Evidence is found for an increase of the clustering amplitude with increasing redshift. These measurements allow to further…

The origin of radio emission in different populations of radio-quiet quasars is relatively unknown, but recent work has uncovered various drivers of increased radio-detection fraction. In this work, we pull together three known factors:…

We investigate the populations and evolution of normal and active galaxies by extending the infrared source count model of Rowan-Robinson (2001) into the radio. The FIR-radio correlation is used to extend the SEDs to the radio region and it…

We use new 144 MHz observations over 5634 deg$^2$ from the LOFAR Two-metre Sky Survey (LoTSS) to compile the largest sample of uniformly-selected, spectroscopically-confirmed quasars from the 14th data release of the Sloan Digital Sky…

Fundamental differences in the radio properties of red quasars (QSOs), as compared to blue QSOs, have been recently discovered, positioning them as a potential key population in the evolution of galaxies and black holes across cosmic time.…

We present a new approach to tackle the issue of radio loudness in quasars. We constrain a (simple) prescription for the intrinsic distribution of radio-to-optical ratios by comparing properties of Monte Carlo simulated samples with those…

The quasar sample selected by cross-correlating the FIRST and the 2dF Quasar Redshift Surveys allows us to explore, for the first time, the faint end of the radio and optical luminosity functions up to z = 2.2. We find indications (~3…

The majority of quasars are weak in their radio emission, with flux densities comparable to those in the optical, and energies far lower. A small fraction, about 10%, are hundreds to thousands of times stronger in the radio. Conventional…

We cross match the NVSS and FIRST surveys with three large photometric catalogues of luminous red galaxies (LRGs) to define radio-loud samples. These have median redshifts 0.35, 0.55 and 0.68 and, by matching rest-frame optical and radio…

I discuss two programs to study radio-loud quasars at high (z>4) redshift. Quasars are the most luminous, non-transient objects known and are observed to the earliest cosmic epochs. At lower redshifts, radio-loud quasars are associated with…

Deep optical images have been gathered for a nearly complete sample of radio galaxies from the Revised 3rd Cambridge (3CR) Catalog in the redshift range 0.15 < z < 0.65. Total and nuclear magnitudes and colors have been extracted. The…