Phase-Resolved Timing Analysis of GRS 1915+105 in Its {\rho} State

TL;DR

This study conducts a detailed phase-resolved timing analysis of GRS 1915+105 in its { ho} state, revealing correlations between LFQPO properties and spectral features, suggesting a common origin across different states.

Contribution

It provides the first detailed phase-resolved analysis of LFQPOs in the { ho} state and links timing features to spectral properties, highlighting the corona's role.

Findings

LFQPO frequency correlates with spectral index, not inner disk radius.

LFQPO amplitude spectrum is consistent with corona-related origin.

LFQPO properties are similar across different spectral states.

Abstract

We made a phase-resolved timing analysis of GRS 1915+105 in its {\rho} state and obtained detailed {\rho} cycle evolutions of the frequency, the amplitude and the coherence of low-frequency quasi-periodic oscillation (LFQPO). We combined our timing results with the spectral study by Neilsen et al. to perform an elaborate comparison analysis. Our analyses show that the LFQPO frequency does not scale with the inner disk radius, but it is related to the spectral index, indicating a possible correlation between the LFQPOs and the corona. The LFQPO amplitude spectrum and other results are naturally explained by tying the LFQPO to the corona. The similarities of the spectra of variability parameters between the LFQPO from {\rho} state and those from more steady states indicate that the LFQPOs of GRS 1915+105 in very different states seem to share the same origin.