Results 51 to 60 of about 132,127 (94)
M94 as a Unique Testbed for Black Hole Mass Estimates and AGN Activity at Low Luminosities
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 We discuss the peculiar nature of the nucleus of M94 (NGC 4736) in the context of new measurements of the broad Hα emission from HST‐STIS observations. We show that this component is unambiguously associated with the high‐resolution X‐ray, radio, and variable UV sources detected at the optical nucleus of this galaxy.
Anca Constantin +2 more
wiley +1 more source
Extended Narrow-Line Region in Seyfert Galaxies
Frontiers in Astronomy and Space Sciences, 2017 We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks) in the different
Enrico Congiu +10 more
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
Recoiling Black Holes: Electromagnetic Signatures, Candidates, and Astrophysical Implications
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 Supermassive black holes (SMBHs) may not always reside right at the centers of their host galaxies. This is a prediction of numerical relativity simulations, which imply that the newly formed single SMBH, after binary coalescence in a galaxy merger, can receive kick velocities up to several 1000 km/s due to anisotropic emission of gravitational waves ...
S. Komossa, Francesca Civano
wiley +1 more source
Probing extreme black‐hole outflows on short timescales via high spectral‐resolution x‐ray imagers
Astronomische Nachrichten, Volume 345, Issue 6-7, July-August 2024.Abstract We investigate outflows and the physics of super‐Eddington versus sub‐Eddington regimes in black hole systems. Our focus is on prospective science using next‐generation high‐resolution soft x‐ray instruments. We highlight the properties of black hole ultraluminous x‐ray source (ULX) systems in particular. Owing to scale invariance in accreting
C. Pinto +9 more
wiley +1 more source
The Cosmic History of Black Hole Growth from Deep Multiwavelength Surveys
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 Significant progress has been made in the last few years on understanding how supermassive black holes form and grow. In this paper, we begin by reviewing the spectral signatures of active galactic nuclei (AGN) ranging from radio to hard X‐ray wavelengths.
Ezequiel Treister +2 more
wiley +1 more source
AGN Obscuration and the Unified Model
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 Unification Models of Active Galactic Nuclei postulate that all the observed differences between type 1 and type 2 objects are due to orientation effects with respect to the line of sight to the observer. The key ingredient of these models is the obscuring medium, historically envisaged as a toroidal structure on a parsec scale.
Stefano Bianchi +3 more
wiley +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
On the Hadronic Origin of High-energy Emission of γ-Ray-loud Narrow-line Seyfert 1 PKS 1502+036
The Astrophysical Journal, 2023 The radiation mechanism of Radio-Loud Narrow-Line Seyfert 1 (RL-NLS1) galaxies from X-ray to γ -ray bands remains an open question. While the leptonic model has been employed to explain the spectral energy distribution (SED), the hadronic process may ...
Zhen-Jie Wang +3 more
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