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Complex Phase Lag Behaviors of the 0.5 - 10 Hz QPOs in GRS 1915+105

D. Lin·I. A. Smith·E. P. Liang·M. Böttcher
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Abstract

Through studying the hard lags between the soft (3.3 - 5.8 keV) and hard (13.0 - 41.0 keV) photons of the 0.5 - 10 Hz QPOs in GRS 1915+105, we have classified them into three types: 0.5 - 2.0 Hz QPOs, 2.0 - 4.5 Hz QPOs, and 4.5 - 10 Hz QPOs. They are closely related to different temporal and spectral states. The first type of QPOs (0.5 - 2 Hz) have positive hard lags at both the QPO fundamental and first harmonic frequencies. These QPOs were observed in the quiescent soft state. The second type of QPOs (2 - 4.5 Hz), which were also detected in the quiescent soft state, have opposite signs of hard lags at the QPO fundamental and first harmonic frequencies. The third type (4.5 - 10 Hz), which showed up in medium soft quiescent/out-burst states, do not have significant higher harmonic peaks. There is a smooth transition between these three types of QPO behaviors. We did not detect 0.5 - 10 Hz QPOs in the very soft state. We discuss some of the implications of these results.

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D. Lin, I. A. Smith, E. P. Liang, M. Böttcher. 2000-10-06. Complex Phase Lag Behaviors of the 0.5 - 10 Hz QPOs in GRS 1915+105. https://arxiv.org/abs/astro-ph/0010139

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