0025012 - ASÚ 2006 RIV DE eng J - Článek v odborném periodiku
Bursa, Michal
Global oscillations of a fluid torus as a modulation mechanism for black-hole high-frequency QPOs.
[Globální oscilace plynéeho torusu jako mechanismus modulace HFQPO v černých dírách.]
Astronomische Nachrichten. Roč. 9, č. 326 (2005), s. 849-855. ISSN 0004-6337. E-ISSN 1521-3994
Výzkumný záměr: CEZ:AV0Z1003909
Klíčová slova: black hole physics * gravitation * X-rays
Kód oboru RIV: BN - Astronomie a nebeská mechanika, astrofyzika
Impakt faktor: 0.871, rok: 2005

We study strong-gravity effects on modulation of radiation emerging from accreting compact objects as a possible mechanism for flux modulation in QPOs. We construct a toy model of an oscillating torus in the slender approximation assuming thermal bremsstrahlung for the intrinsic emissivity of the medium and we compute observed (predicted) radiation signal including contribution of indirect (higher-order) images and caustics in the Schwarzschild spacetime. We show that the simplest oscillation mode in an accretion flow, axisymmetric up-and-down motion at the meridional epicyclic frequency, may be directly observable when it occurs in the inner parts of accretion flow around black holes. Together with the second oscillation mode, an in-and-out motion at the radial epicyclic frequency, it may then be responsible for the high-frequency modulations of the /mbox{X-ray} flux observed at two distinct frequencies (twin HF-QPOs) in micro-quasars.

Globální oscilace plynného torusu jako mechanismus modulace HFQPO v černých dírách
Trvalý link: http://hdl.handle.net/11104/0115464