47 citations · 285 across the 18 of their papers we have counts for
18 papers
Modeling X-ray reflection spectra from disk returning radiation: Application to 4U 1630-47
Kostas Kourmpetis, Shafqat Riaz, Honghui Liu +6
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 reflec…
Assessing the Power-Law Emissivity Assumption in X-ray Reflection Spectroscopy: A Simulation-Based Evaluation of Different Coronal Geometries
Songcheng Li, Abdurakhmon Nosirov, Cosimo Bambi +3
The emissivity profile assumed in X-ray reflection spectroscopy significantly impacts black hole spin measurements. Using simulated NuSTAR spectra generated for lamppost and disk-l…
X-ray reflection spectroscopy with improved calculations of the emission angle
Yimin Huang, Honghui Liu, Temurbek Mirzaev +10
The reflection spectrum produced by a cold medium illuminated by X-ray photons is not isotropic and its shape depends on the emission angle. In the reflection spectrum of an accret…
X-ray spectra of black hole X-ray binaries with returning radiation
Temurbek Mirzaev, Cosimo Bambi, Askar B. Abdikamalov +4
In the disk-corona model, the X-ray spectrum of a stellar-mass black hole in an X-ray binary is characterized by three components: a thermal component from a thin and cold accretio…
Towards more accurate synthetic reflection spectra: improving the calculations of returning radiation
Temurbek Mirzaev, Shafqat Riaz, Askar B. Abdikamalov +6
We present a new model to calculate reflection spectra of thin accretion disks in Kerr spacetimes. Our model includes the effect of returning radiation, which is the radiation that…
About the ability of agnostic X-ray tests of the Kerr Hypothesis to discover new physics
Shuaitongze Zhao, Shafqat Riaz, Cosimo Bambi
In the past decade, we have seen an unprecedented progress in our ability of testing general relativity in the strong field regime with black hole observations. Most studies have f…
Testing General Relativity with Black Hole X-Ray Data and ABHModels
Cosimo Bambi, Askar B. Abdikamalov, Honghui Liu +3
The past 10 years have seen tremendous progress in our capability of testing General Relativity in the strong field regime with black hole observations. 10 years ago, the theory of…
Testing Regular Black Holes with X-ray data of GX 339-4
Shafqat Riaz, Michail Kyriazis, Askar B. Abdikamalov +2
Regular black holes are singularity-free black hole spacetimes proposed to solve the problem of the presence of spacetime singularities that plagues the black holes of general rela…
Impact of the returning radiation in current tests of the Kerr black hole hypothesis using X-ray reflection spectroscopy
Shafqat Riaz, Temurbek Mirzaev, Askar B. Abdikamalov +1
The past 10 years have seen remarkable progress in our capability of analyzing reflection features in the X-ray spectra of accreting black holes. Today X-ray reflection spectroscop…
Unveiling the contribution of Pop III stars in primeval galaxies at redshift
Shafqat Riaz, Tilman Hartwig, Muhammad A. Latif
Detection of the first stars has remained elusive so-far but their presence may soon be unveiled by upcoming JWST observations. Previous studies have not investigated the entire po…
Testing relativistic reflection models with GRMHD simulations of accreting black holes
Swarnim Shashank, Shafqat Riaz, Askar B. Abdikamalov +1
X-ray reflection spectroscopy is currently one of the leading techniques for studying the inner part of accretion disks around black holes, measuring black hole spins, and even tes…
Probing bumblebee gravity with black hole X-ray data
Jiale Gu, Shafqat Riaz, Askar B. Abdikamalov +2
Bumblebee gravity is one of the simplest gravity theories with spontaneous Lorentz symmetry breaking. Since we know a rotating black hole solution in bumblebee gravity, we can pote…
Testing regular black holes with X-ray and GW data
Shafqat Riaz, Swarnim Shashank, Rittick Roy +5
The presence of spacetime singularities in physically relevant solutions of the Einstein Equations is normally interpreted as a symptom of the breakdown of classical general relati…
Testing the Weak Equivalence Principle near black holes
Rittick Roy, Askar B. Abdikamalov, Dimitry Ayzenberg +3
Today we have quite stringent constraints on possible violations of the Weak Equivalence Principle from the comparison of the acceleration of test-bodies of different composition i…
Reflection spectra of accretion disks illuminated by disk-like coronae
Shafqat Riaz, Askar B. Abdikamalov, Dimitry Ayzenberg +3
Relativistic reflection features in the X-ray spectra of black hole binaries and AGNs are thought to be produced through illumination of a cold accretion disk by a hot corona. In t…
Impact of the returning radiation on the analysis of the reflection spectra of black holes
Shafqat Riaz, Michal Szanecki, Andrzej Niedzwiecki +2
A fraction of the electromagnetic radiation emitted from the surface of a geometrically thin and optically thick accretion disk of a black hole returns to the disk because of the s…
Modeling bias in supermassive black hole spin measurements
Shafqat Riaz, Dimitry Ayzenberg, Cosimo Bambi +1
X-ray reflection spectroscopy (or iron line method) is a powerful tool to probe the strong gravity region of black holes, and currently is the only technique for measuring the spin…
Reflection spectra of thick accretion disks
Shafqat Riaz, Dimitry Ayzenberg, Cosimo Bambi +1
Relativistic reflection features are commonly observed in the X-ray spectra of stellar-mass and supermassive black holes and originate from illumination of the inner part of the ac…