The 67 HZ Feature in the Black Hole Candidate GRS 1915+105 as a Possible ``Diskoseismic'' Mode
Abstract
The Rossi X-Ray Timing Explorer 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 Msolar (nonrotating) to 36.3 Msolar (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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1997
- DOI:
- 10.1086/310534
- arXiv:
- arXiv:astro-ph/9612142
- Bibcode:
- 1997ApJ...477L..91N
- Keywords:
-
- BLACK HOLE PHYSICS;
- X-RAYS: STARS;
- Black Hole Physics;
- X-Rays: Stars;
- Astrophysics
- E-Print:
- 4 Pages, Latex (emulateapj.sty included), to Appear in ApJ Letters, Vol. 477, Final Version with Updated References