M. A. Nowak, R. V. Wagoner, M. C. Begelman, D. E. Lehr
Published 1996-12-13, updated 1997-01-24Version 2
The Rossi X-ray Timing Explorer (RXTE) has made feasible for the first time the search for high-frequency (~ 100 Hz) periodic features in black hole candidate (BHC) systems. Such a feature, with a 67 Hz frequency, recently has been discovered in the BHC GRS 1915+105 (Morgan, Remillard, & Greiner). This feature is weak (rms variability ~0.3%-1.6%), stable in frequency (to within ~2 Hz) despite appreciable luminosity fluctuations, and narrow (quality factor Q ~ 20). Several of these properties are what one expects for a ``diskoseismic'' g-mode in an accretion disk about a 10.6 M_sun (nonrotating) - 36.3 M_sun (maximally rotating) black hole (if we are observing the fundamental mode frequency). We explore this possibility by considering the expected luminosity modulation, as well as possible excitation and growth mechanisms---including turbulent excitation, damping, and ``negative'' radiation damping. We conclude that a diskoseismic interpretation of the observations is viable.
Comments: 4 Pages, Latex (emulateapj.sty included), to Appear in ApJ Letters, Vol. 477, Final Version with Updated References
On the source of QPO of the black hole candidate GRS1915+105: some new observations and their interpretation
Hard X-Ray Spectra of Broad-Line Radio Galaxies from the Rossi X-Ray Timing Explorer
Observation of Cen A by the Rossi X-ray Timing Explorer
