Related papers: Accretion of matter and spectra of Binary X-ray so…
This study focuses on the X-ray emission of low-mass black hole binaries in massive Brans-Dicke gravity. First, we compute the accretion disk adopting the well-known Shakura-Sunyaev model for an optically thick, cool, and geometrically thin…
Stellar-mass black holes offer what is perhaps the best scenario to test theories of gravity in the strong-field regime. In particular, f(R) theories, which have been widely discuss in a cosmological context, can be constrained through…
The accretion-ejection activities of black holes play a vital role in shaping the Universe. Bright and recurrent black hole X-ray binaries are ideal objects for studying accretion physics across a wide range of accretion rates, providing…
Current astrophysical research suggests that the most persistently luminous objects in the Universe are powered by the flow of matter through accretion disks onto black holes. Accretion disk systems are observed to emit copious radiation…
X-ray spectroscopy of galactic black hole binaries serve as a powerful tool to gain an overall understanding of the system. Not only can the properties of the accretion disk be studied in detail, the fundamental properties of the black hole…
X-ray binaries, as bright local sources with short variability timescales for a wide range of accretion processes, represent ideal targets for high-resolution X-ray spectroscopy. In this chapter, we present a high-resolution X-ray spectral…
Accreting black holes are believed to emit X-rays which then mediate information about strong gravity in the vicinity of the emission region. We report on a set of new routines for the Xspec package for analysing X-ray spectra of black-hole…
Hard X-ray emission is ubiquitous in accreting black holes, both in Galactic binary systems and in Active Galactic Nuclei. I review the different spectra which can be seen from these systems, and possible ways of producing this emission.…
Accretion onto black holes is one of the most efficient energy source in the Universe. Black hole accretion powers some of the most luminous objects in the universe, including quasars, active galactic nuclei, tidal disruption events,…
Relativistic reflection features are commonly observed in the X-ray spectra of accreting black holes. In the presence of high quality data and with the correct astrophysical model, X-ray reflection spectroscopy can be quite a powerful tool…
Disc spectra from highly luminous black hole binaries are observed to be rather simple, despite theoretical predictions to the contrary. We collate the disc-dominated spectra from multiple observations of 10 separate sources, and show that…
Fitting the thermal continuum emission of accreting black holes observed across X-ray bands represents one of the principle means of constraining the properties (mass and spin) of astrophysical black holes. Recent ''continuum fitting''…
Electromagnetic observations have been used over the past decades to understand the nature of black holes and the material around them. Our ability to learn about the fundamental physics relies on our understanding of two key ingredients in…
The X-ray Background (XRB) probably originates from the integrated X-ray emission of active galactic nuclei (AGN). Modelling of its flat spectrum implies considerable absorption in most AGN. Compton down-scattering means that sources in…
We present a general relativistic accretion disc model and its application to the soft-state X-ray spectra of black hole binaries. The model assumes a flat, optically thick disc around a rotating Kerr black hole. The disc locally radiates…
The models that seek to explain the reflection spectrum in black hole binaries usually invoke a point-like primary source of hard X-rays. This source illuminates the accretion disk and gives rise to the discrete (lines) and…
Accretion disks around black holes radiate a significant fraction of the rest mass of the accreting material in the form of thermal radiation from within a few gravitational radii of the black hole ($ r \lesssim 20 G M / c^{2}$). In…
Recent X-ray observations of Galactic Black Hole Candidates and AGNs and Seyfert galaxies reveal the broad emission lines in their spectra, which can arise in the innermost parts of accretion disks. Simulation indicates that at low…
The analysis of the properties of the X-ray radiation emitted from geometrically thin accretion disks around black holes can be a powerful tool to test General Relativity in the strong field regime. This chapter reviews the state-of-the-art…
In this paper we obtain and study images of accretion disks around static spherically symmetric black holes in hybrid metric-Palatini gravity. We use Novikov-Thorne thin-disk model. Semi-analytic ray-tracing methods in curved spacetime are…