Results 81 to 90 of about 261,296 (275)
SEYFERT GALAXIES: NUCLEAR RADIO STRUCTURE AND UNIFICATION [PDF]
, 2011 A radio study of a carefully selected sample of 20 Seyfert galaxies that are matched in orientation-independent parameters, which are measures of intrinsic active galactic nucleus power and host galaxy properties, is presented to test the predictions of ...
D. Lal, P. Shastri, D. Gabuzda
semanticscholar +1 more source
A Practical Guide to the Massive Black Hole Cosmic History
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 I review our current understanding of massive black hole (MBH) formation and evolution along the cosmic history. After a brief introductory overview of the relevance of MBHs in the hierarchical structure formation paradigm, I discuss the main viable channels for seed BH formation at high redshift and for their subsequent mass growth and spin evolution.
A. Sesana, Francesco Shankar
wiley +1 more source
Clustering of X‐Ray‐Selected AGN
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 The study of the angular and spatial structure of the X‐ray sky has been under investigation since the times of the Einstein X‐ray Observatory. This topic has fascinated more than two generations of scientists and slowly unveiled an unexpected scenario regarding the consequences of the angular and spatial distribution of X‐ray sources.
N. Cappelluti +3 more
wiley +1 more source
The Astrophysical JournalWe analyze a sample of ~113,000 galaxies ( z
Huynh Anh N. Le, Yongquan Xue
doaj +1 more source
Relativistic reflection spectra of super-spinning black holes
European Physical Journal C: Particles and Fields, 2020 We construct a relativistic reflection model in a non-Kerr spacetime in which, depending on the value of the deformation parameter of the metric, there are black hole solutions with spin parameter $$|a_*| > 1$$ |a∗|>1 .
Biao Zhou +6 more
doaj +1 more source
The Astrophysical Journal Supplement Series, 2023 We analyze a sample of 21 “bare” Seyfert 1 active galactic nuclei, a subclass of Seyfert 1 galaxies, with intrinsic absorption N _H ∼ 10 ^20 cm ^−2 , in the local Universe ( z < 0.2) using XMM-Newton and Swift/XRT observations.
Prantik Nandi +7 more
doaj +1 more source
Kinematic differences between NLS1 and BLAGN sources
, 2018 It is well-known that the higher policyclic aromatic hydrocarbon (PAH) abundance, lower black hole mass, higher accretion rate and lower luminosities are among the major characteristics of Narrow-Line Seyfert galaxies (NLS1), when they are compared to ...
Kovačević-Dojčinović, J. +2 more
core +1 more source
Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies [PDF]
, 2017 We studied the optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z < 0.8 to investigate any differences in their OV properties.
S. Rakshit, C. .. Stalin
semanticscholar +1 more source
ASCA observations of type-2 Seyfert Galaxies. III. Orientation and X-ray Absorption
, 1997 We discuss the spectral properties of a sample of type-2 Seyfert galaxies based upon the analysis of \asca data. In this paper we consider the sources for which the X-ray spectra appear to be dominated by the nuclear continuum, transmitted through a ...
Antonucci R. +24 more
core +1 more source
The far-infrared energy distributions of Seyfert and starburst galaxies in the Local Universe: ISO photometry of the 12 micron active galaxy sample [PDF]
, 2002 New far-infrared photometry with ISOPHOT, onboard the Infrared Space Observatory, is presented for 58 galaxies with homogeneous published data for another 32 galaxies all belonging to the 12 micron galaxy sample.
Alton P. B. +14 more
core +2 more sources