Testing the dynamic origin of Quasi-periodic Oscillations in MAXI J1535-571 and H 1743-322

TL;DR

This study analyzes spectro-temporal data from two black hole X-ray binaries, supporting the idea that type-C QPOs originate from dynamic frequencies related to sound crossing times in the accretion disk.

Contribution

It provides evidence favoring the dynamic frequency model for type-C QPOs over relativistic precession, based on combined spectral and temporal analysis.

Findings

QPO frequency correlates with accretion rate and inner disc radius.

Spectral analysis shows relativistic effects and disc truncation.

Results support the dynamic frequency origin of type-C QPOs.

Abstract

We investigate spectro-temporal properties for two black hole X-ray binary sources, MAXI J1535$-$571 and H 1743$-$322, during their hard and hard-intermediate states. For MAXI J1535$-$571, we analyze Swift/XRT, NuSTAR and NICER observations, specifically focusing on the occurrence of type-C Quasi-periodic Oscillations (QPOs). Regarding H 1743$-$322, we analyze multi-epoch observations of NICER and AstroSat, identifying a type-C QPO with centroid frequency ranging from 0.1--0.6 Hz. In both sources, we fit the spectra with a relativistic truncated disk and a power law component. In MAXI J1535$-$571, we also observe an additional relativistically smeared iron line. Through temporal and spectral analysis, we estimate the QPO centroid frequency and spectral parameters, such as the accretion rate and inner disc radii. We test the origin of type-C QPOs as relativistic precession frequency and dynamic frequency (i.e. the inverse of the sound crossing time $\frac{r}{c_s(r)}$). The dependence of QPO frequency on both the accretion rate and inner disc radii favours the QPO origin as dynamic frequency. We discuss the implications of these results.