Physics
Scientific paper
Aug 2006
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006iaujd...6e..17p&link_type=abstract
Neutron Stars and Black Holes in Star Clusters, 26th meeting of the IAU, Joint Discussion 6, 17-18 August 2006, Prague, Czech Re
Physics
Scientific paper
Quasi-periodic oscillations (QPOs) have been observed in accretion disks around compact stars with frequencies ranging from a few 0.1 Hz up to 1300 Hz. A correlation between their low- and high-frequency components was discovered and fitted with a single law, irrespective of the nature of the accreting star. That such a relation holds over 6~orders of magnitude strongly supports the idea that the physical mechanism responsible for these oscillations should be the same in all binary systems. We propose a new model for these QPOs based on forced oscillations induced in a relativistic accretion disk due to an asymmetric component in the stellar gravitational or magnetic field. It is shown that the disk experiences three kinds of resonances: corotation, Lindblad, and parametric resonance. 2D numerical simulations are in agreement with the aforementioned linear analysis. They are performed for the Newtonian gravitational potential, as well as for a pseudo-general relativistic potential. Density perturbations are only significant in the region near the innermost stable circular orbit (ISCO) where the perturbation is maximal. It is argued that the nearly periodic motion induced in the disk will produce high quality factor QPOs. Moreover, this model also explains the segregation between slow and fast rotating neutron stars. Indeed, the strongest resonance occurs when the frequency difference of the two highest modes equals either the spin frequency (for ``slow rotators'') or half of it (for ``fast rotators''). This discrimination is interpreted as a direct manifestation of the presence of an ISCO. Nevertheless, strong gravity is not needed to excite the modes.
No associations
LandOfFree
Forced Oscillations In Relativistic Accretion Discs And QPOs does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Forced Oscillations In Relativistic Accretion Discs And QPOs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Forced Oscillations In Relativistic Accretion Discs And QPOs will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1783658