J 2007

Epicyclic oscillations of fluid bodies: Newtonian nonslender torus

BLAES, Omer, Eva ŠRÁMKOVÁ, Marek ABRAMOWICZ, Wlodel KLUZNIAK, Ulf TORKELSSON et. al.

Basic information

Original name

Epicyclic oscillations of fluid bodies: Newtonian nonslender torus

Authors

BLAES, Omer, Eva ŠRÁMKOVÁ, Marek ABRAMOWICZ, Wlodel KLUZNIAK and Ulf TORKELSSON

Edition

Astrophysical Journal, CHICAGO, UNIV CHICAGO PRESS, 2007, 0004-637X

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Confidentiality degree

není předmětem státního či obchodního tajemství

Organization unit

Faculty of Philosophy and Science in Opava

DOI

UT WoS

000248675700047

Keywords in English

accretion, accretion disks; black hole physics; hydrodynamics; X-rays : binaries

Tags

Změněno: 12/4/2021 14:17, RNDr. Kateřina Klimovičová, Ph.D.

Abstract

V originále

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 eigenfrequencies V-r and V-z 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 V-z/V-r = 3/2, which is important for the theory of high-frequency quasi-periodic oscillations (QPOs), occurs when the fluid tori epicyclic frequencies V-r and V-z 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.