Optical appearance of a compact binary system in the neighbourhood of supermassive black hole

TL;DR

This paper models the optical appearance of a compact binary star near a supermassive black hole, deriving key expressions and analyzing redshift and pulsar timing in a strong gravitational field.

Contribution

It introduces a formalism for calculating the optical and timing effects on binary stars in the vicinity of a supermassive black hole, including new equations of motion.

Findings

Derived expressions for redshift, magnification, and pulsar extinction time.

Analyzed redshift evolution and pulse arrival times in strong gravitational fields.

Applied model to a binary system near a Schwarzschild black hole.

Abstract

Optical appearance of a compact binary star in the field of a supermassive black hole is modeled in a strong field regime. Expressions for the redshift, magnification coefficient and pulsar extinction time are derived. By using the vierbein formalism we have derived equations of motion of compact binary star in the external gravitational field. We have analysed both the evolution of redshift of the optical ray from the usual star or white dwarf, and the times of arrival of pulses of pulsar. The results are illustrated by a calculation for a model binary system for the case of external gravitational field of a Schwarzschild black hole. The obtained results can be used for fitting timing data from the X-ray pulsars that moves in the neighbourhood of the Galactic Center (Sgr A*).