Related papers: Relativistic reflection within an extended hot pla…
We present the publicly available model \textsc{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 disk and are…
The inclination angle of substructures in active galaxies gives insights into physical components from scales of the vicinity of the central black hole to the entire host galaxy. We use the self-consistent reflection spectral model…
Accretion disk reflection spectra, including broad iron emission lines, bear the imprints of the strong Doppler shifts and gravitational red-shifts close to black holes. The extremity of these shifts depends on the proximity of the…
The X-ray spectra of accreting stellar-mass black hole systems exhibit spectral features due to reflection, especially broad iron K alpha emission lines. We investigate the reflection by the accretion disc that can be expected in the…
We present a detailed spectral analysis of the black hole candidate MAXI J1836-194. The source was caught in the intermediate state during its 2011 outburst by Suzaku and RXTE. We jointly fit the X-ray data from these two missions using the…
Understanding the dynamics behind black hole state transitions and the changes they reflect in outbursts has become long-standing problem. The X-ray reflection spectrum describes the interaction between the hard X-ray source (the power-law…
Accreting black holes show characteristic 'reflection' features in their X-ray spectra, including the iron K$\alpha$ fluorescence line, which result from X-rays radiated by a compact central corona being reprocessed in the accretion disc…
We discuss black hole spin measurements employing the relativistic iron line profiles in the X-ray domain. We investigate the iron line band for two representative sources -- MCG -6-30-15 (active galaxy) and GX 339-4 (X-ray binary). We…
Returning radiation is thought to play a key role in disk illumination of black hole X-ray binaries in the high-soft state, yet it has not been fully incorporated into XSPEC reflection models. We present a new table model for reflection…
X-ray reflection off the accretion disc surrounding a black hole, together with the associated broad iron K$\alpha$ line, has been widely used to constrain the innermost accretion-flow geometry and black hole spin. Some recent measurements…
We present a time-resolved analysis of high-resolution spectra of the AGN MCG-6-30-15 obtained by XRISM alongside broadband spectra from NuSTAR and XMM-Newton during a coordinated observing campaign in February 2024. These observations…
There are many simplifications in current relativistic reflection models and this introduces systematic uncertainties in the measurement of the properties of the source. In this paper, we study the impact of the radiation crossing the…
X-ray reflection spectroscopy is a powerful tool for probing the strong gravity region of black holes and can be used for testing general relativity in the strong field regime. Simplifications of the available relativistic reflection models…
We study the lamppost model, in which the primary X-ray sources in accreting black-hole systems are located symmetrically on the rotation axis on both sides of the black hole surrounded by an accretion disc. We show the importance of the…
Accretion around black holes is very often characterized by distinctive X-ray reflection features (mostly, iron inner-shell transitions), which arise due to the primary radiation being reprocessed by a dense and relatively colder medium,…
X-ray reflection spectroscopy has evolved as one of the leading methods to measure black hole spins. However, the question is whether its measurements are subjected to systematic biases, especially considering the possible discrepancy…
The X-ray emission from bright active galactic nuclei (AGNs) is believed to originate in a hot corona lying above a cold, geometrically thin accretion disk. A highly concentrated corona located within $\sim10$ gravitational radii above the…
Special and general relativistic effects on the X-ray emissions, especially the continuum spectra, from the accretion disks around black holes are investigated using the ray-tracing method. Because both the special and general relativistic…
Accretion disc model fitting to optical/UV quasar spectra requires that the highest mass black holes have the highest spin, with implications on the hierarchical growth of supermassive black holes and their host galaxies over cosmic time.…
This Thesis describes the basic framework and applications of a relativistic ray-tracing code for analyzing accretion processes around Kerr black holes. We begin in Chapter 1 with a brief historical summary of the major advances in black…