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Testing General Relativity with NuSTAR data of Galactic Black Holes
Ashutosh Tripathi, Yuexin Zhang, Askar B. Abdikamalov +5
Einstein's theory of General Relativity predicts that the spacetime metric around astrophysical black holes is described by the Kerr solution. In this work, we employ state-of-the-…
Towards precision measurements of accreting black holes using X-ray reflection spectroscopy
Cosimo Bambi, Laura W. Brenneman, Thomas Dauser +14
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,…
Testing the Kerr Black Hole Hypothesis with GX 339-4 by a combined analysis of its thermal spectrum and reflection features
Ashutosh Tripathi, Askar B. Abdikamalov, Dimitry Ayzenberg +3
We analyze simultaneous observations with NuSTAR and Swift of the black hole binary GX 339-4 in which we clearly detect both a strong thermal component and prominent relativistic r…
A Possible -ray Quasi-periodic Oscillation of 314 days in the Blazar OJ 287
Pankaj Kushwaha, Arkadipta Sarkar, Alok C. Gupta +3
We report the detection of a probable -ray quasi-periodic oscillation (QPO) of around 314 days in the monthly binned 0.1 -- 300 GeV -ray {\it Fermi}-LAT light curve of the we…
Testing the Keplerian disk hypothesis using X-ray reflection spectroscopy
Ashutosh Tripathi, Biao Zhou, Askar B. Abdikamalov +3
The Novikov-Thorne model is the standard framework for the description of geometrically thin and optically thick accretion disks around black holes and is widely used to study the…
Impact of the reflection model on the estimate of the properties of accreting black holes
Ashutosh Tripathi, Honghui Liu, Cosimo Bambi
Relativistic reflection features in the X-ray spectra of black hole binaries and AGNs originate from illumination of the inner part of the accretion disk by a hot corona. In the pr…
Shining X-rays on asymptotically safe quantum gravity
Biao Zhou, Askar B. Abdikamalov, Dimitry Ayzenberg +3
Asymptotically safe quantum gravity is a promising candidate scenario to provide a UV extension for the effective quantum field theory of Einstein's gravity. The theory has its fou…
X-ray reflection spectroscopy with Kaluza-Klein black holes
Jiachen Zhu, Askar B. Abdikamalov, Dimitry Ayzenberg +6
Kaluza-Klein theory is a popular alternative theory of gravity, with both non-rotating and rotating black hole solutions known. This allows for the possibility that the theory coul…
Thermal spectra of thin accretion disks of finite thickness around Kerr black holes
Menglei Zhou, Askar B. Abdikamalov, Dimitry Ayzenberg +3
The analysis of the thermal spectrum of geometrically thin and optically thick accretion disks of black holes, the so-called continuum-fitting method, is one of the leading techniq…
Testing the Kerr black hole hypothesis using X-ray reflection spectroscopy and a thin disk model with finite thickness
Askar B. Abdikamalov, Dimitry Ayzenberg, Cosimo Bambi +5
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. Sim…
Testing general relativity with the stellar-mass black hole in LMC X-1 using the continuum-fitting method
Ashutosh Tripathi, Menglei Zhou, Askar B. Abdikamalov +6
The iron line and the continuum-fitting methods are currently the two leading techniques for measuring black hole spins with electromagnetic radiation. They can be naturally extend…