Results 31 to 40 of about 58,921 (147)
Imprints of the super-Eddington accretion on the quasar clustering
, 2017 Super-Eddington mass accretion has been suggested as an efficient mechanism to grow supermassive black holes (SMBHs). We investigate the imprint left by the radiative efficiency of the super-Eddington accretion process on the clustering of quasars using ...
Enoki, Motohiro +7 more
core +1 more source
The Luminosity Dependence of Quasar Clustering
, 2005 We investigate the luminosity dependence of quasar clustering, inspired by numerical simulations of galaxy mergers that incorporate black hole growth. These simulations have motivated a new interpretation of the quasar luminosity function.
Adam Lidz +8 more
core +1 more source
Quasars Probing Quasars. II. The Anisotropic Clustering of Optically Thick Absorbers around Quasars [PDF]
The Astrophysical Journal, 2007 With close pairs of quasars at different redshifts, a background quasar sightline can be used to study a foreground quasar's environment in absorption. We used a sample of 17 Lyman limit systems with column density N_HI > 10^19 cm^-2 selected from 149 projected quasar pair sightlines, to investigate the clustering pattern of optically thick ...
Joseph F. Hennawi, Jason X. Prochaska
openaire +3 more sources
New Astronomy Reviews, 2000 We propose a simple unifying structure for the inner regions of quasars and AGN. This empirically derived model links together the BALs, the narrow UV/X-ray ionized absorbers, the BELR, and the Compton scattering/fluorescing regions into a single structure. The model also suggests an origin for the large-scale bi-conical outflows.
openaire +5 more sources
ISO Observations of Quasars and Quasar Hosts [PDF]
, 1997 The Infrared Space Observatory (ISO), launched in November 1995, allows us to measure the far-infrared (far-IR) emission of quasars in greater detail and over a wider energy range than previously possible. In this paper, preliminary results in a study of the 5--200 $ m$ continuum of quasars and active galaxies are presented. Comparison of the spectral
openaire +3 more sources
Large SDSS quasar groups and their statistical significance
, 2015 We use a volume-limited sample of quasars in the Sloan Digital Sky Survey (SDSS) DR7 quasar catalog to identify quasar groups and address their statistical significance.
Einasto, Maret +4 more
core +1 more source
Journal of Applied Clinical Medical Physics, EarlyView.Abstract Purpose This study aims to evaluate the accuracy of the frameless linear accelerator‐based stereotactic radiosurgery (FSRS) system incorporating cone‐beam CT (CBCT), six degrees of freedom (6‐DoF) couch, room laser, and surface image‐guided (SG) systems.
Hao‐Wen Cheng +4 more
wiley +1 more source
SDSS J094604.90+183541.8: A Gravitationally Lensed Quasar at z=4.8
, 2010 We report the discovery of a gravitationally lensed quasar identified serendipitously in the Sloan Digital Sky Survey (SDSS). The object, SDSS J094604.90+183541.8, was initially targeted for spectroscopy as a luminous red galaxy, but the SDSS spectrum ...
Abazajian +48 more
core +1 more source
Journal of Applied Clinical Medical Physics, EarlyView.Abstract Purpose This study aims to evaluate how different gantry angles, breathing rates (BPM), cine image speeds, and tracking algorithms affect beam on/off latency and the subsequent impact on target dose for a 0.35T MR‐Linac with a 6 MV FFF beam.
Mateb Al Khalifa +4 more
wiley +1 more source
Modeling the HeII Transverse Proximity Effect: Constraints on Quasar Lifetime and Obscuration
, 2017 The HeII transverse proximity effect - enhanced HeII Ly{\alpha} transmission in a background sightline caused by the ionizing radiation of a foreground quasar - offers a unique opportunity to probe the emission properties of quasars, in particular the ...
Davies, Frederick B. +5 more
core +1 more source