Epicyclic Oscillations of Fluid Bodies: Newtonian Nonslender Torus
We study epicyclic oscillations of fluid tori around black holes (in the Paczynski-Wiita potential) and derive exact analytic expressions for their radial and vertical eigenfrequendes [unk] and v2 to second-order accuracy in the width of the torus. We prove that pressure effects make the eigenfreque...
Gespeichert in:
Veröffentlicht in: | The Astrophysical journal 2007-08, Vol.665 (1), p.642-653 |
---|---|
Hauptverfasser: | , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext bestellen |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | We study epicyclic oscillations of fluid tori around black holes (in the Paczynski-Wiita potential) and derive exact analytic expressions for their radial and vertical eigenfrequendes [unk] and v2 to second-order accuracy in the width of the torus. We prove that pressure effects make the eigenfrequencies smaller than those for free particles. However, the particular ratio v2/ [unk] = 3/2, which is important for the theory of high-frequency quasi-periodic oscillations (QPOs), occurs when the fluid tori epicyclic frequencies [unk] and v2 are about 15% higher than the ones corresponding to free particles. Our results therefore suggest that previous estimates of black hole spins from QPOs have produced values that are too high. |
---|---|
ISSN: | 0004-637X 1538-4357 |
DOI: | 10.1086/519782 |