A study of the strong gravity region of the black hole in GS 1354-645

Understand

It is thought that the spacetime metric around astrophysical black holes is well described by the Kerr solution of Einstein's gravity.

• However, a robust observational evidence of the Kerr nature of these objects is still lacking.
• Here we fit the X-ray spectrum of the stellar-mass black hole in GS 1354-645 with a disk reflection model beyond Einstein's gravity in order test the Kerr black hole hypothesis.
• We consider the Johannsen metric with the deformation parameters $\alpha_{13}$ and $\alpha_{22}$.