Testing the Kerr hypothesis using X-ray reflection spectroscopy with NuSTAR data of Cygnus X-1 in the soft state

Abstract

We continue exploring the constraining capabilities of X-ray reflection spectroscopy to test the Kerr-nature of astrophysical black holes and we present the results of our analysis of two NuSTAR observations of Cygnus X-1 in the soft state. We find that the final measurement can strongly depend on the assumption of the intensity profile. We conclude that Cygnus X-1 is not suitable for tests of general relativity using X-ray reflection spectroscopy and we discuss the desired properties of a source to be a good candidate for our studies.

15 pages, 8 figures. v2: refereed version

References in corpus (11)

• The Confrontation between General Relativity and Experiment
• Constraining Black Hole Spin Via X-ray Spectroscopy
• X-ray reverberation around accreting black holes
• Testing the black hole "no-hair" hypothesis
• An absorption origin for the X-ray spectral variability of MCG-6-30-15
• Constraints on the spacetime geometry around 10 stellar-mass black hole candidates from the disk's thermal spectrum
• The absorption-dominated model for the X-ray spectra of type I active galaxies: MCG-6-30-15
• Constraints on the spacetime metric around seven "bare" AGNs using X-ray reflection spectroscopy
• Note on the effect of a massive accretion disk in the measurements of black hole spins
• About the Kerr nature of the stellar-mass black hole in GRS 1915+105
• Constraining the Johannsen deformation parameter ${\epsilon }_3$ with black hole X-ray data