Models of quasi-periodic oscillations related to mass and spin of the GRO J1655-40 black hole

TL;DR

This study compares various QPO models for the black hole GRO J1655-40 with observed frequencies to estimate its mass and spin, finding several models consistent with optical measurements and discussing their implications.

Contribution

The paper evaluates multiple QPO models against observational data to constrain the black hole's mass and spin, extending models to include low-frequency QPOs and comparing results with optical and X-ray measurements.

Findings

Relativistic precession model predicts mass ~5.3 M_sun and spin ~0.286.

Total precession model estimates mass ~5.5 M_sun and spin ~0.276.

Resonance epicyclic model with beat frequency yields mass ~5.1 M_sun and spin ~0.274.

Abstract

Frequencies of the three quasi-periodic oscillation (QPO) modes observed simultaneously in the accreting black hole GRO J1655-40 are compared with the predictions of models. Models in which all three QPO signals are produced at the same radius are considered: these include different versions of relativistic precession, epicyclic resonance, tidal disruption, and warped disc models. Models that were originally proposed to interpret only the twin high-frequency QPOs are generalized here to interpret also the low-frequency QPO in terms of relativistic nodal precession. Inferred values of the black hole mass and spin from each QPO model are compared with the mass measured from optical observations and the spin inferred from X-ray spectroscopy techniques. We find that along with the relativistic precession model predicting $M=(5.3\pm0.1)~M_{\odot}, a=0.286\pm0.004$, the so-called total precession model ($M=(5.5\pm0.1)~M_{\odot}, a=0.276\pm0.003$), and the resonance epicyclic model with beat frequency ($M=(5.1\pm0.1)~M_{\odot}, a=0.274\pm0.003$) also satisfy the optical mass test. We compare our results with those inferred from X-ray spectral measurements.