Testing the Kerr Nature of Black Hole Candidates using Iron Line Spectra in the CPR Framework

Understand

The iron K$\alpha$ line commonly observed in the X-ray spectrum of both stellar-mass and supermassive black hole candidates originates from X-ray fluorescence of the inner accretion disk.

• Accordingly, it can be used to map the spacetime geometry around these objects.
• In this paper, we extend previous work using the iron K$\alpha$ line to test the Kerr black hole hypothesis.
• We adopt the Cardoso-Pani-Rico parametrization and we test the possibility of constraining possible deviations from the Kerr solution that can be obtained from observations across the range of black hole spins and inclination angles.