Discovery of correlated optical/X-ray quasi-periodic oscillations in black hole binary SWIFT J1753.5-0127

TL;DR

This paper reports the discovery of correlated optical and X-ray low-frequency QPOs in the black hole binary SWIFT J1753.5-0127, providing insights into the emission mechanisms and accretion flow dynamics.

Contribution

It presents the first detection of correlated optical/X-ray QPOs in this system and models the QPOs as resulting from Lense-Thirring precession of the hot accretion flow.

Findings

QPO phase lag is close to zero, constraining emission models.

The broadband optical variability is explained by hot flow and irradiated disc.

A lower limit on orbital inclination is established at >50 degrees.

Abstract

We report the discovery of the correlated optical/X-ray low-frequency quasi-periodic oscillations (QPOs) in black hole binary SWIFT J1753.5-0127. The phase lag between two light-curves at the QPO frequency is close to zero. This result puts strong constraints on the nature of the optical emission in this object and on the origin of the QPOs in general. We demonstrate that the QPO signal and the broadband variability can be explained in terms of the hot accretion flow radiating in both optical and X-ray bands. In this model, the QPO appears due to the Lense-Thirring precession of entire flow, while the broadband variability in the optical is produced by two components: the hot flow and the irradiated disc. Using the phase-lag spectra, we put a lower limit on the orbital inclination i>50 deg, which can be used to constrain the mass of the compact object.