Epicyclic oscillations and accretion disk around a special Buchdahl-inspired spacetime

TL;DR

This paper investigates the properties of a Buchdahl-inspired spacetime, analyzing particle orbits, epicyclic oscillations, and accretion disk characteristics, with implications for astrophysical observations and constraints on spacetime parameters.

Contribution

It provides a detailed analysis of geodesics, QPOs, and accretion disk features in a Buchdahl-inspired spacetime, extending understanding beyond Schwarzschild black holes.

Findings

ISCO radii decrease with increasing Buchdahl parameter {k}

Derived expressions for epicyclic oscillations in this spacetime

Constraints on spacetime parameters from QPO observations

Abstract

In this paper, we consider the Buchdahl-inspired spacetime metric and investigate its aspects using the quasiperiodic oscillations and the accretion disk due to the accreting matter. First, we focus on analyzing the geodesics of particles around the Buchdahl-inspired spacetime, together with the conserved quantities such as specific energy and angular momentum for massive particles orbiting on the innermost stable circular orbits (ISCOs). We show that the effect of the Buchdahl parameter $\tilde{k}$ increases as the radii of the ISCO orbits decrease, resulting in shifting orbits toward the central object compared to the Schwarzschild black hole case. We also consider astrophysical epicyclic oscillations and derive their general expressions using implications of circular motion of massive particles around the Buchdahl-inspired spacetime. Further, we explore the astrophysical implications of observational higher-frequency QPOs of the selected galactic microquasars of X-ray binary systems to obtain the best-fit constraints on the Buchdahl-inspired spacetime parameters. Finally, we consider the accretion disk around the Buchdahl-inspired spacetime using implications of the ISCO parameters that define the accretion disk's inner edge. We explore radiation properties of the accretion disk and redshifted image and intensity of a lensed accretion disk around the Buchdahl-inspired spacetime.