Publication date: Mar 2015
Abstract:
The model of current-carrying string loop oscillations is tested to
explain the special set of frequencies related to the high-frequency
quasiperiodic oscillations (HF QPOs) observed recently in the low-mass
X-ray binary XTE J1701-407 containing a neutron star. The external
geometry of the neutron star is approximated by the Kerr geometry,
introducing errors not exceeding 10 % for slowly rotating massive
neutron stars. The frequencies of the radial and vertical string loop
oscillations are then governed by the mass and dimensionless spin of the
neutron star, and by the dimensionless parameter describing combined
effects of the string loop tension and its angular momentum. It is
explicitly demonstrated that the string-loop oscillation model can
explain the observed kHz frequencies for the neutron star parameters
restricted to the intervals and . However, the stringy parameter cannot
be the same for all the three HF QPO observations in the XTE J1701-407
source; the limits on the acceptable values of are given in dependence
on the spacetime parameters and.
Authors:
Stuchlík, Z.; Kološ, M.;