Přehled o publikaci

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 governedby the mass M and dimensionless spin a of the neutron star, and by the dimensionless parameter omega describing combined effects of the string loop tension and its angular momentum. It is explicitly demonstrated that the string-loop oscillation model canexplain the observed kHz frequencies for the neutron star parameters restricted to the intervals 0.2 < a < 0.4 and 2.1 < M/M_{circle dot} < 2.5. However, the stringy parameter omega cannot be the same for all the three HF QPO observation