English
Related papers

Related papers: A low-luminosity type-1 QSO sample; III. Optical s…

200 papers

JWST observations have uncovered a new population of red, compact objects at high redshifts dubbed `Little Red Dots' (LRDs), which typically show broad emission lines and are thought to be dusty Active Galactic Nuclei (AGN). Some of their…

Narrow-line Seyfert 1 galaxies (NLS1s) are a subclass of active galactic nuclei (AGN). It is often believed that these AGN have small black hole mass, which is responsible for the narrowness of the permitted lines. They are also…

Astrophysics of Galaxies · Physics 2018-09-27 A. Vietri , M. Berton , S. Ciroi , E. Congiu , G. La Mura , V. Cracco , M. Frezzato , S. Chen , A. Cattapan , T. Peruzzi , P. Rafanelli

We present the far-IR, millimeter, and radio photometry as well as optical and near-IR spectroscopy of a sample of 48 z~1-3 Spitzer-selected ULIRGs with IRS mid-IR spectra. Our goals are to compute their bolometric emission, and to…

The maximum number density of Active Galactic Nuclei (AGNs), as deduced from X-ray studies, occurs at z<~1, with lower luminosity objects peaking at smaller redshifts. Optical studies lead to a different evolutionary behaviour, with a…

Astrophysics · Physics 2009-11-13 D. Trevese , F. Vagnetti , S. Puccetti , F. Fiore , M. Tomei , M. A. Bershady

This paper addresses, for the first time, a key aspect of the phenomenology of Compact Symmetric Objects (CSOs) -- the characteristics of their radio spectra. We present a radio-spectrum description of a complete sample of high luminosity…

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…

Broad absorption line quasars (BALQSOs) are key objects for studying the structure and emission/absorption properties of AGN. However, despite their fundamental importance, the properties of BALQSOs are still not well understood. In order…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 A. Streblyanska , X. Barcons , F. J. Carrera , R. Gil-Merino

The radio-loud/radio-quiet (RL/RQ) dichotomy in quasars is still an open question. Although it is thought that accretion onto supermassive black holes in the centre the host galaxies of quasars is responsible for some radio continuum…

We detect and study the properties of faint radio AGN in Luminous Red Galaxies (LRGs). The LRG sample comprises 760,000 objects from a catalog of LRG photometric redshifts constructed from the Sloan Digital Sky Survey (SDSS) imaging data,…

Astrophysics of Galaxies · Physics 2015-05-13 J. A. Hodge , G. R. Zeimann , R. H. Becker , R. L. White

We present the selection of high-redshift ($z\gtrsim5.7$) radio-loud (RL) quasi-stellar object (QSO) candidates from the combination of the radio Rapid ASKAP Continuum Survey (RACS; at 888 MHz) and the optical/near-infrared Dark Energy…

Astrophysics of Galaxies · Physics 2022-12-28 L. Ighina , A. Caccianiga , A. Moretti , S. Belladitta , J. W. Broderick , G. Drouart , J. K. Leung , N. Seymour

We present an analysis of the properties of optical counterparts of radio sources down to 1 mJy. Optical identifications have been obtained by matching together objects from the APM and FIRST surveys over the region $148.13^\circ\simlt {\rm…

Astrophysics · Physics 2009-11-06 M. Magliocchetti , S. J. Maddox

(Abridged) We report on the X-ray and multiwavelength properties of 11 radio-quiet quasars with weak or no emission lines identified by the Sloan Digital Sky Survey (SDSS) with redshift z=0.4-2.5. The distribution of relative X-ray…

We study the properties of the emission line regions in two samples of low luminosity radio-galaxies (LLRG), focusing on the compact emission line region (CELR) revealed to be a characteristic feature of these objects by HST narrow-band…

Astrophysics · Physics 2009-11-11 Alessandro Capetti , Gijs Verdoes Kleijn , Marco Chiaberge

An unprecedentedly large number of LINERs has been discovered in a recently completed optical spectroscopic survey of nearby galaxies, allowing several statistical properties of the host galaxies and of the line-emitting regions to be…

Astrophysics · Physics 2007-05-23 Luis C. Ho

We present a sub-arcsec resolution radio imaging survey of a sample of 76 low-luminosity active galactic nuclei (LLAGN) that were previously not detected with the Very Large Array at 15 GHz. Compact, parsec-scale radio emission has been…

High Energy Astrophysical Phenomena · Physics 2018-09-12 Payaswini Saikia , Elmar Körding , Deanne L. Coppejans , Heino Falcke , David Williams , Ranieri D. Baldi , Ian Mchardy , Rob Beswick

We present Spitzer IRS low resolution, mid-IR spectra of a sample of 25 high luminosity QSOs at 2<z<3.5. When combined with archival IRS observations of local, low luminosity type-I AGNs, the sample spans five orders of magnitude in…

Astrophysics · Physics 2009-11-13 R. Maiolino , O. Shemmer , M. Imanishi , H. Netzer , E. Oliva , D. Lutz , E. Sturm

We present 6 cm Very Large Array observations of the Greene & Ho (2004) sample of 19 low-mass active galaxies with high accretion rates. This is one of the only studies of a uniform sample of narrow-line Seyfert 1 (NLS1) galaxies with such…

Astrophysics · Physics 2009-11-13 Jenny E. Greene , Luis C. Ho , James S. Ulvestad

This is the third paper of a series describing the Asiago-ESO/RASS QSO survey (AERQS), a project aimed at the construction of an all-sky statistically well-defined sample of relatively bright QSOs (B<15) at z<0.3. We present here the…

We present observations at 1.2 mm with MAMBO-II of a sample of z>~2 radio-intermediate obscured quasars, as well as CO observations of two sources with the Plateau de Bure Interferometer. Five out of 21 sources (24%) are detected at a…

We present Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) data on the large-scale environments of 16 0.39 < z < 0.51 quasars from the Large Bright Quasar Survey (LBQS). The LBQS quasars are representative of the…

Astrophysics · Physics 2007-05-23 R. A. Finn , C. D. Impey , E. J. Hooper