Periodic X-ray Modulation and its relation with orbital elements in Compact Binaries

TL;DR

This study detects periodic X-ray modulations in compact binaries caused by tidal forces related to orbital eccentricity, offering a new method to determine orbital parameters from X-ray data.

Contribution

It introduces a novel approach to estimate orbital periods and eccentricities of compact binaries using X-ray modulation analysis.

Findings

Periodic X-ray modulations observed in several compact binaries.

Eccentricities estimated from RMS power of quasi-orbital peaks.

Method provides an independent way to determine orbital parameters.

Abstract

Stellar companion of a black hole orbiting in an eccentric orbit will experience modulating tidal force with a periodicity same as that of the orbital period. This, in turn, would modulate accretion rates, and the seed photon flux which are inverse Comptonized to produce harder X-rays. By analyzing complete all sky monitor (ASM) data (1.5-12 keV) of RXTE and all sky survey data (15-50 keV) of Swift/BAT we discover this periodicity in several objects. We also estimate eccentricities from the RMS power of the peak around quasi-orbital periods (QOP). Our method provides an independent way to obtain time periods and eccentricities of such compact binaries.