Journal Article

Association of the 3:2 HFQPO pairs with the broad Fe K line in XTE J1550−564 and GRO J1655−40

Ding-Xiong Wang, Zhao-Ming Gan, Chang-Yin Huang and Yang Li

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 391, issue 3, pages 1332-1340
Published in print December 2008 | ISSN: 0035-8711
Published online November 2008 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2008.13965.x
Association of the 3:2 HFQPO pairs with the broad Fe K line in XTE J1550−564 and GRO J1655−40

Show Summary Details

Preview

Association of the high-frequency quasi-periodic oscillation (HFQPO) pairs with the broad Fe K line in XTE J1550−564 and GRO J1655−40 is discussed based on the magnetic coupling of a rotating black hole (BH) with its surrounding disc. The 3:2 HFQPO pairs are interpreted by virtue of the inner and outer hotspots arising from non-axisymmetric magnetic field, where the inner hotspot is produced by a torque exerted at the inner edge of the disc, and the outer hotspot is created by the screw instability of the large-scale magnetic field. The very steep emissivity index is created predominantly by the torque exerted at the inner edge of the disc. It turns out that the 3:2 HFQPO pairs observed in the two sources can be fitted by tuning several model parameters, such as the BH spin, and the main features of this model lie in three aspects. (1) The condition for only one HFQPO is discussed based on the two mechanisms for producing the 3:2 HFQPO pairs, (2) an explanation is given for a systematic shift away from disc dominated flux with the increasing power-law flux as the HFQPO pairs shift from the higher to lower frequencies, which is consistent with the analysis given by Remillard et al. and (3) the BH spin in XTE J1550−564 and GRO J1655−40 can be estimated by combining the 3:2 HFQPO pairs with the very steep emissivity index required for fitting the broad Fe K emission line.

Keywords: accretion, accretion discs; black hole physics; magnetic fields; stars: individual: XTE J1550−564; stars: individual: GRO J1655−40; stars: oscillations

Journal Article.  5987 words.  Illustrated.

Subjects: Astronomy and Astrophysics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.