J 2005

QPOs in microquasars and Sgr A*: measuring the black hole spin

TÖRÖK, Gabriel

Basic information

Original name

QPOs in microquasars and Sgr A*: measuring the black hole spin

Edition

Astronomische Nachrichten, WEINHEIM, WILEY-V C H VERLAG GMBH, 2005, 0004-6337

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

UT WoS

000233488500014

Keywords in English

black hole physics; X-ray variability

Tags

International impact, Reviewed
Změněno: 12/4/2021 14:13, RNDr. Kateřina Klimovičová, Ph.D.

Abstract

V originále

In all four microquasars which show double peak kHz QPOs, the ratio of the two frequencies is 3:2. This strongly supports the suggestion that twin peak kHz QPOs are due to a resonance between some modes of accretion disk oscillations. Here, we stress that fits to observations of the hypothetical resonances between vertical and radial epicyclic frequencies (particularly of the parametric resonance) give an accurate estimate of the spin for the three microquasars with known mass. Measurement of double peak QPOs frequencies in the Galaxy centre seems also to be consistent with the 3:2 ratio established by previous observations in microquasars, however the Sgr A* data are rather difficult for the same exact analysis. If confirmed, the 3:2 ratio of double peak QPOs in Sgr A* would be of a fundamental importance for the black hole accretion theory and the precise measurement could help to solve the question of QPOs nature.