scholarly journals Correlation between the photon index and X-ray luminosity of black hole X-ray binaries and active galactic nuclei: observations and interpretation

2014 ◽  
Vol 447 (2) ◽  
pp. 1692-1704 ◽  
Author(s):  
Qi-Xiang Yang ◽  
Fu-Guo Xie ◽  
Feng Yuan ◽  
Andrzej A. Zdziarski ◽  
Marek Gierliński ◽  
...  
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
X Ray ◽  
Photon Index ◽  
X Ray Binaries

scholarly journals Radiative efficiency of hot accretion flow and the radio/X-ray correlation in X-ray binaries

2014 ◽  
Vol 10 (S312) ◽  
pp. 139-140
Author(s):  
Fu-Guo Xie
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Accretion Rate ◽  
Galactic Nuclei ◽  
X Ray ◽  
Radiative Efficiency ◽  
Accretion Flow ◽  
Accretion Rates ◽  
Distinctive Property ◽  
X Ray Binaries

AbstractSignificant progresses have been made since the discovery of hot accretion flow, a theory successfully applied to the low-luminosity active galactic nuclei (LLAGNs) and black hole (BH) X-ray binaries (BHBs) in their hard states. Motivated by these updates, we re-investigate the radiative efficiency of hot accretion flow. We find that, the brightest regime of hot accretion flow shows a distinctive property, i.e. it has a constant efficiency independent of accretion rates, similar to the standard thin disk. For less bright regime, the efficiency has a steep positive correlation with the accretion rate, while for faint regime typical of advection-dominated accretion flow, the correlation is shadower. This result can naturally explain the observed two distinctive correlations between radio and X-ray luminosities in black hole X-ray binaries. The key difference in systems with distinctive correlations could be the viscous parameter, which determines the critical luminosity of different accretion modes.

scholarly journals A public relativistic transfer function model for X-ray reverberation mapping of accreting black holes

2019 ◽  
Vol 488 (1) ◽  
pp. 324-347 ◽  
Author(s):  
Adam Ingram ◽  
Guglielmo Mastroserio ◽  
Thomas Dauser ◽  
Pieter Hovenkamp ◽  
Michiel van der Klis ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Radial Profile ◽  
Galactic Nuclei ◽  
Seyfert Galaxy ◽  
Geometric Constraints ◽  
Time Lags ◽  
X Ray ◽  
X Ray Binaries

ABSTRACTWe present the publicly available model reltrans that calculates the light-crossing delays and energy shifts experienced by X-ray photons originally emitted close to the black hole when they reflect from the accretion disc and are scattered into our line of sight, accounting for all general relativistic effects. Our model is fast and flexible enough to be simultaneously fit to the observed energy-dependent cross-spectrum for a large range of Fourier frequencies, as well as to the time-averaged spectrum. This not only enables better geometric constraints than only modelling the relativistically broadened reflection features in the time-averaged spectrum, but additionally enables constraints on the mass of supermassive black holes in active galactic nuclei and stellar-mass black holes in X-ray binaries. We include a self-consistently calculated radial profile of the disc ionization parameter and properly account for the effect that the telescope response has on the predicted time lags. We find that a number of previous spectral analyses have measured artificially low source heights due to not accounting for the former effect and that timing analyses have been affected by the latter. In particular, the magnitude of the soft lags in active galactic nuclei may have been underestimated, and the magnitude of lags attributed to thermal reverberation in X-ray binaries may have been overestimated. We fit reltrans to the lag-energy spectrum of the Seyfert galaxy Mrk 335, resulting in a best-fitting black hole mass that is smaller than previous optical reverberation measurements (∼7 million compared with ∼14–26 million M⊙).

scholarly journals The X-ray spectral evolution and radio–X-ray correlation in radiatively efficient black-hole sources

2014 ◽  
Vol 10 (S312) ◽  
pp. 249-251
Author(s):  
Ai-Jun Dong ◽  
Qingwen Wu ◽  
Xiao-Feng Cao
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Spectral Evolution ◽  
Critical Flux ◽  
Fundamental Plane ◽  
X Ray ◽  
Data Points ◽  
X Ray Binaries

AbstractWe explore X-ray spectral evolution and radio–X-ray correlation simultaneously for four X-ray binaries (XRBs). We find that hard X-ray photon indices, Γ, are anti- and positively correlated to X-ray fluxes when the X-ray flux, F3–9keV, is below and above a critical flux, FX,crit, which may be regulated by ADAF and disk-corona respectively. We find that the data points with anti-correlation of Γ-F3–9keV follow the universal radio–X-ray correlation of FR ∝ FXb (b ~ 0.5-0.7), while the data points with positive X-ray spectral evolution follow a steeper radio–X-ray correlation (b ~ 1.4, the so-called ‘outliers track’). The bright active galactic nuclei (AGNs) share similar X-ray spectral evolution and radio–X-ray correlation as XRBs in ‘outliers’ track, and we present a new fundamental plane of log LR=1.59+0.28−0.22 log LX−0.22+0.19−0.20 log MBH−28.97+0.45−0.45 for these radiatively efficient BH sources.

scholarly journals A NuSTAR census of coronal parameters in Seyfert galaxies

2018 ◽  
Vol 614 ◽  
pp. A37 ◽  
Author(s):  
A. Tortosa ◽  
S. Bianchi ◽  
A. Marinucci ◽  
G. Matt ◽  
P. O. Petrucci
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Optical Depth ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
Black Hole Mass ◽  
Significance Level ◽  
X Ray ◽  
Photon Index ◽  
Hot Corona

Context. We discuss the results of the hot corona parameters of active galactic nuclei (AGN) that have been recently measured with NuSTAR. The values taken from the literature of a sample of 19 bright Seyfert galaxies are analysed. Aims. The aim of this work is to look for correlations between coronal parameters, such as the photon index and cut-off energy (when a phenomenological model is adopted) or the optical depth and temperature (when a Comptonization model is used), and other parameters of the systems, such as the black hole mass or the Eddington ratio. Methods. We analysed the coronal parameters of the 19 unobscured, bright Seyfert galaxies that are present in the Swift/BAT 70-month catalogue and that have been observed by NuSTAR, alone or simultaneously with others X-ray observatories, such as Swift, Suzaku, or XMM-Newton. Results. We found an anti-correlation with a significance level >98% between the coronal optical depth and the coronal temperature of our sample. On the other hand, no correlation between the above parameters and the black hole mass, the accretion rate, and the intrinsic spectral slope of the sources is found.

scholarly journals Correlation between relativistic reflection fraction and photon index in NuSTAR sample of Seyfert 1 AGN

2020 ◽  
Vol 495 (3) ◽  
pp. 3373-3386
Author(s):  
Savithri H Ezhikode ◽  
Gulab C Dewangan ◽  
Ranjeev Misra ◽  
Ninan Sajeeth Philip
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Relativistic Effects ◽  
Accretion Disc ◽  
Telescope Array ◽  
X Ray ◽  
Photon Index ◽  
The Relationship ◽  
Reflection Component

ABSTRACT The primary X-ray emission from active galactic nuclei (AGNs), described by a power-law, irradiates the accretion disc producing reflection features in the spectrum. The reflection features arising from the inner regions of the disc can be significantly modified by the relativistic effects near the black hole. We investigate the relationship between the relativistic reflection fraction Rf, defined as the ratio of the coronal intensity that illuminates the accretion disc to the coronal intensity observed directly, and the hard X-ray photon index Γ of a Nuclear Spectroscopic Telescope Array (NuSTAR) sample of Seyfert 1 galaxies. The X-ray spectra are modelled using relxill code that helps to directly obtain the reflection fraction of a relativistically smeared reflection component. The parameter Rf depends on the amount of Comptonized X-ray emission intercepted by the inner accretion disc. We found a positive correlation between Γ and Rf in our sample. Seed photons from a larger area of an accretion disc entering the corona will result in increased cooling of the coronal plasma, giving rise to steeper X-ray spectrum. The corona irradiating the larger area of the disc will result in higher reflection fraction. Thus, the observed Rf –Γ relation is most likely related to the variations in the disc–corona geometry of AGNs.

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