Eccentric equatorial trajectories around a Kerr black hole as a QPO model for M82X-1

TL;DR

This paper models high-frequency QPOs in M82X-1 using eccentric equatorial trajectories around a Kerr black hole, providing new insights into the orbital parameters that produce observed oscillations.

Contribution

It introduces a method to infer eccentric and equatorial orbit parameters around Kerr black holes from QPO data, applying it specifically to M82X-1.

Findings

Eccentric orbit solutions are feasible between ISCO and MBCO.

Inferred orbital parameters: eccentricity ~0.277, spin ~0.29, periastron ~4.62.

Probabilistic analysis constrains the orbit characteristics for QPO generation.

Abstract

We study the bound orbit conditions for equatorial and eccentric orbits around a Kerr black hole both in the parameter space ($E$, $L$, $a$) representing the energy, angular momentum of the test particle, and spin of the black hole, and also ($e$, $\mu$, $a$) space representing the eccentricity, inverse-latus rectum of the orbit, and spin. We apply these conditions and implement the relativistic precession (RP) model to M82X-1, which is an Intermediate-mass black hole (IMBH) system, where two high-frequency Quasi-Periodic Oscillations (HFQPOs) and a low-frequency QPO were simultaneously observed. Assuming that the QPO frequencies can also be generated by equatorial and eccentric trajectories, we calculate the probability distributions to infer $e$, $a$, and periastron distance, $r_p$, of the orbit giving rise to simultaneous QPOs. We find that an eccentric orbit solution is possible in the region between innermost stable circular orbit (ISCO) and the marginally bound circular orbit (MBCO) for $e=0.2768^{+0.0657}_{-0.0451}$, $a=0.2897 \pm 0.0087$, and $r_p=4.6164^{+0.0694}_{-0.1259}$.