Discovery of a 34 Hz Quasi-Periodic Oscillation in the X-ray emission of GRS 1915+105

TL;DR

This paper reports the discovery of a 34 Hz quasi-periodic oscillation in GRS 1915+105, observed simultaneously with a 68 Hz oscillation, providing new insights into the source's timing properties.

Contribution

The paper presents the first detection of a 34 Hz QPO in GRS 1915+105, expanding the known frequency spectrum of its X-ray oscillations.

Findings

Detection of a 34 Hz QPO with 4.2 sigma significance

Simultaneous observation of 34 Hz and 68 Hz QPOs

Correlation with specific spectral states of GRS 1915+105

Abstract

We report the discovery in the Rossi X-Ray Timing Explorer data of GRS 1915+105 of a second quasi-periodic oscillation at 34 Hz, simultaneous with that observed at 68 Hz in the same observation. The data corresponded to those observations from 2003 where the 68-Hz oscillation was very strong. The significance of the detection is 4.2 sigma. These observations correspond to a very specific position in the colour-colour diagram for GRS 1915+105, corresponding to a harder spectrum compared to those where a 41 Hz oscillation was discovered. We discuss the possible implications of the new pair of frequencies comparing them with the existing theoretical models.