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.;