Probing the near-horizon region of Cygnus X-1 with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>S</mml:mi><mml:mi>u</mml:mi><mml:mi>z</mml:mi><mml:mi>a</mml:mi><mml:mi>k</mml:mi><mml:mi>u</mml:mi></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>N</mml:mi><mml:mi>u</mml:mi><mml:mi>S</mml:mi><mml:mi>T</mml:mi><mml:mi>A</mml:mi><mml:mi>R</mml:mi></mml:math>
Аннотация
Astrophysical black holes are ideal laboratories for testing Einstein's theory of general relativity in the strong field regime. In this manuscript, we present an analysis of $Suzaku$ and $NuSTAR$ spectra of the black hole binary Cygnus X-1 using relxill_nk. Unlike our previous study on Cygnus X-1 with $NuSTAR$ data, here we are able to constrain the Johannsen deformation parameter ${\ensuremath{\alpha}}_{13}$. However, despite the high energy resolution near the iron line provided by $Suzaku$, our constraints on the Kerr metric from Cygnus X-1 are not very stringent in comparison with those that have been obtained from other sources, confirming that Cygnus X-1 is quite a complicated source.