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[30.03] ``Voice-prints" within the unstable light curves of GRS 1915+105: QPOs at 165 and 113 Hz

R. A. Remillard, M. P. Muno (M.I.T.), J. E. McClintock (CfA), J. A. Orosz (SDSU)

We have begun sorting the wildly varying light curves of GRS 1915+105 into binned intervals defined by the X-ray intensity and spectral hardness, in order to isolate power density spectra for different phases of the instability. A portion of some "theta" type light curves (classification of Belloni et al.) produces a QPO (and harmonics) at 165 (3) Hz, while a portion of some "nu" type light curves produces a QPO near 113 (3) Hz. These QPOs do not occur at the same time, but they have nearly commensurate frequencies (3:2 ratio). These results support two conclusions. First, our data selections suggest that the QPOs at 113 and 165 Hz appear to be caused by the same mechanism that produces QPO pairs in GRO J1655-40 (300, 450 Hz) and XTE J1550-564 (184, 276 Hz). Second, the results provide additional support for the conjecture that fast X-ray QPOs in black hole binaries represent some type of resonance condition rooted in general relativity.

Bulletin of the American Astronomical Society, 35#2
© 2003. The American Astronomical Soceity.