Accretion onto a static spherically symmetric regular MOG dark compact object

TL;DR

This paper investigates how a modified gravity theory (MOG) affects accretion processes and particle motion around a regular spherically symmetric dark compact object, providing analytical insights into ISCO and energy flux modifications.

Contribution

It offers the first analytical study of accretion and particle dynamics in a regular MOG dark compact object, highlighting the impact of MOG parameters on accretion features.

Findings

MOG parameter increases the ISCO radius for neutral and charged particles.

MOG parameter decreases the energy flux of accreting matter.

Energy density and radial velocity of infalling fluid decrease with higher MOG parameter.

Abstract

In astrophysics, the process of a massive body acquiring matter is referred to as accretion. The extraction of gravitational energy occurs as a result of the infall. Since it converts gravitational energy into radiation, accretion onto dark compact objects, e.g. black holes, neutron stars, and white dwarfs is an extremely significant process in the astrophysical context. Accretion process is a fruitful way to explore the features of modified gravity (MOG) theories by testing the behavior of their solutions associated with dark compact objects. In this paper, we study the motion of electrically neutral and charged particles moving in around a regular spherically symmetric MOG dark compact object to explore their related innermost stable circular orbit (ISCO) and energy flux. Then, we turn to investigate the accretion of perfect fluid onto the regular spherically symmetric MOG dark compact object. We obtain analytical expressions for four-velocity and proper energy density of the accreting fluid. We see that the MOG parameter increases the ISCO radius of either electrically neutral or charged test particles while it decreases the corresponding energy flux. Moreover, the energy density and the radial component of the four-velocity of the infalling fluid decrease by increasing the MOG parameter near the central source.