scholarly journals BEYOND THE STANDARD MODEL OF THE DISC–LINE SPECTRAL PROFILES FROM BLACK HOLE ACCRETION DISCS

2014 ◽  
Vol 54 (4) ◽  
pp. 300-304
Author(s):  
Vjaceslav Sochora ◽  
Vladimír Karas ◽  
Jirí Svoboda ◽  
Michal Dovciak
Keyword(s):  
Black Hole ◽  
Gravitational Field ◽  
Spectral Line ◽  
Galactic Nuclei ◽  
Accretion Disc ◽  
Beyond The Standard Model ◽  
Black Hole Accretion ◽  
The Standard Model ◽  
Spectral Profiles ◽  
Hole Accretion

The strong gravitational field of a black hole has distinct effects on the observed profile of a spectral line from an accretion disc near a black hole. The observed profile of the spectral line is broadened and skewed by a fast orbital motion and redshifted by a gravitational field. These effects can help us to constrain the parameters of a system with a black hole, both in active galactic nuclei and in a stellar-mass black hole. Here we explore the fact that an accretion disc emission can be mathematically imagined as a superposition of radiating accretion rings that extend from the inner edge to the outer rim of the disc, with some radially varying emissivity. In our work, we show that a characteristic double-horn profile of several radially confined (relatively narrow) accretion rings or belts could be recognized by the planned instruments onboard future satellites (such as the proposed ESA Large Observatory for X-ray Timing).

scholarly journals Spectral and polarization properties of black hole accretion disc emission: including absorption effects

2020 ◽  
Author(s):  
R Taverna ◽  
L Marra ◽  
S Bianchi ◽  
M Dovčiak ◽  
R Goosmann ◽  
...  
Keyword(s):  
Black Hole ◽  
Polarization State ◽  
General Rule ◽  
Accretion Disc ◽  
Accretion Discs ◽  
Polarization Degree ◽  
Monte Carlo Code ◽  
Black Hole Spin ◽  
Black Hole Accretion ◽  
Hole Accretion

Abstract The study of radiation emitted from black hole accretion discs represents a crucial way to understand the main physical properties of these sources, and in particular the black hole spin. Beside spectral analysis, polarimetry is becoming more and more important, motivated by the development of new techniques which will soon allow to perform measurements also in the X- and γ-rays. Photons emitted from black hole accretion discs in the soft state are indeed expected to be polarized, with an energy dependence which can provide an estimate of the black hole spin. Calculations performed so far, however, considered scattering as the only process to determine the polarization state of the emitted radiation, implicitly assuming that the temperatures involved are such that material in the disc is entirely ionized. In this work we generalize the problem by calculating the ionization structure of a surface layer of the disc with the public code cloudy, and then by determining the polarization properties of the emerging radiation using the Monte Carlo code stokes. This allows us to account for absorption effects alongside scattering ones. We show that including absorption can deeply modify the polarization properties of the emerging radiation with respect to what is obtained in the pure-scattering limit. As a general rule, we find that the polarization degree is larger when absorption is more important, which occurs e.g. for low accretion rates and/or spins when the ionization of the matter in the innermost accretion disc regions is far from complete.

scholarly journals BINARY ACTIVE GALACTIC NUCLEI IN STRIPE 82: CONSTRAINTS ON SYNCHRONIZED BLACK HOLE ACCRETION IN MAJOR MERGERS

2015 ◽  
Vol 815 (1) ◽  
pp. L6 ◽  
Author(s):  
Hai Fu ◽  
J. M. Wrobel ◽  
A. D. Myers ◽  
S. G. Djorgovski ◽  
Lin Yan
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Black Hole Accretion ◽  
Hole Accretion

scholarly journals The starburst – active galactic nuclei connection on nuclear scales in near by Seyfert galaxies

2013 ◽  
Vol 9 (S304) ◽  
pp. 345-346
Author(s):  
Pilar Esquej
Keyword(s):  
Black Hole ◽  
Star Formation ◽  
Formation Rate ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
High Angular Resolution ◽  
Physical Relation ◽  
Black Hole Accretion ◽  
Star Formation Activity ◽  
Hole Accretion

AbstractSeveral works have shown that there is an empirical correlation between the star formation rate and the luminosity of the active galactic nucleus (and thus the black hole accretion rate, ṀBH) of Seyfert galaxies. This suggests a physical relation between the gas forming stars on kpc scales and the gas on sub-pc scales that is feeding the black hole. Simulations predict this relation and also that the correlation should be more prominent on smaller physical scales. We have compiled high angular resolution (0.4–0.8″) mid-infrared spectroscopy obtained with T-ReCS, VISIR, and Michelle of 29 Seyferts. We use the 11.3 μm PAH feature to probe the star formation activity in the inner ~65 pc, and its relation with the ṀBH on these physical scales.

scholarly journals Production of the entire range ofr-process nuclides by black hole accretion disc outflows from neutron star mergers

2016 ◽  
Vol 463 (3) ◽  
pp. 2323-2334 ◽  
Author(s):  
Meng-Ru Wu ◽  
Rodrigo Fernández ◽  
Gabriel Martínez-Pinedo ◽  
Brian D. Metzger
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Entire Range ◽  
Accretion Disc ◽  
Black Hole Accretion ◽  
Hole Accretion
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