Publication date: Dec 2014
Abstract:
The current-carrying string loops oscillating around a stable
equilibrium position in the Kerr background are considered to explain
the twin high-frequency quasiperiodic oscillations (HF QPOs) observed in
the low-mass X-ray binary 4U 1636-53 containing a neutron star. The
frequencies of the radial and vertical string loop oscillations are
governed by the mass and spin parameters of the neutron star, and by the
string parameter describing combined effects of its tension and angular
momentum. The frequencies of the radial and vertical modes of the string
loop oscillations can cover the large scatter of the twin HF QPO data
observed in the 4U 1636-53 source, but the estimates of the mass M and
spin a of the neutron star are rather high, M ̃2.65 M and a ̃ 0.45,
while related to the theory of the neutron star structure. Therefore,
the string loop oscillation model in the case of the 4U 1636-53 source
requires a correction based on an electrically charged string loop
interacting with the magnetic field of the neutron star.
Authors:
Stuchlík, Z.; Kološ, M.;