Discovery of a 34Hz quasi-periodic oscillation in the X-ray emission 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 34Hz, simultaneous with that observed at 68Hz 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 4.2σ. 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. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.