Testing evolution of LFQPOs with mass accretion rate in GRS 1915+105 with Insight-HXMT

TL;DR

This study uses Insight-HXMT observations to analyze the evolution of low frequency QPOs in GRS 1915+105, revealing a strong correlation with mass accretion rate and confirming the black hole's high spin, with implications for testing general relativity.

Contribution

First to extend the correlation between QPO frequency and accretion rate in GRS 1915+105 using independent observations and instruments, confirming the black hole's high spin.

Findings

Positive correlation between QPO frequency and accretion rate

Extension of previous findings to a larger accretion rate range

Confirmation of high black hole spin in GRS 1915+105

Abstract

Using the Insight-HXMT observations of GRS 1915+105 when it exhibits low frequency quasi-periodic oscillations (QPOs), we measure the evolution of the QPO frequency along with disk inner radius and mass accretion rate. We find a tight positive correlation between the QPO frequency and mass accretion rate. Our results extend the finding of previous work with AstroSat to a larger range of accretion rate with independent instruments and observations. Treating the QPO frequency of GRS 1915+105 as the relativistic dynamic frequency of a truncated disk, we are able to confirm the high spin nature of the black hole in GRS 1915+105. We also address the potential of our finding to test general relativity in the future.