Evolution of QPOs in GX 339-4 and EXO 1846-031 with Insight-HXMT and NICER

TL;DR

This study analyzes the evolution of Type-C QPOs in two black hole X-ray binaries using Insight-HXMT and NICER data, revealing their relation to spectral parameters and accretion processes.

Contribution

It provides new insights into the correlation between QPO frequency, inner disk radius, and accretion rate during state transitions.

Findings

QPOs appear at the end of low-hard and hard-intermediate states.

QPO frequency correlates with inner disk radius.

Results support the dynamic frequency model.

Abstract

We conduct a spectral and timing analysis of GX 339-4 and EXO 1846-031 with the aim of studying the evolution of Type-C QPOs with spectral parameters. The high cadence data from Insight-HXMT and NICER allow us to track them. Type-C QPOs appear at the end of low-hard state and/or hard-intermediate state. The results reveal that the QPO frequency is closely related to the inner disk radius and mass accretion rate in the two sources. Such a correlation is nicely consistent with the dynamic frequency model.