Black hole spins in radio-quiet type I active galaxies: Markov chain Monte Carlo based analysis

X-ray emissions from the innermost stable circular orbit (ISCO) regions around supermassive black holes (SMBHs), which have footprints of general-relativistic frame-dragging, give us an insight into SMBH spins. In particular, the active galactic nucleus (AGN) ISCO regions in radio-quiet type I active galaxies with low line-of-sight inclinations are not heavily blocked by the surrounding dusty toroidal regions, so they could be the perfect sample for a spin survey of SMBHs. In this work, an advanced Markov chain Monte Carlo (MCMC) statistical technique is applied to relativistic ray-tracing reflection modeling of the relativistically broadened Fe Kα line at 6.4 keV and the Compton bump above 10 keV in XMM-Newton and NuSTAR archival data of a sample of radio-quiet type I active galaxies, including MCG-6-30-15, NGC 3783, and NGC 4593. Reflection model characteristics such as SMBH spin and inclination angle are well constrained by using the MCMC-based statistical analysis. A further study of a larger sample of radio-quiet type I active galaxies will help us acquire a clearer picture of the effects of black hole spins on regulating AGN outflows and possible impacts on their host active galaxies.