Quasi-periodic oscillations, charge and the gravitomagnetic theory

Abstract

A new model for the explanation of the high frequency quasi-periodic oscillations (QPOs) in pulsars, black holes and white dwarfs is presented. Three circular tori are assumed to be present around the star: an inner torus with charge $Q_i$, an outer torus with charge $Q_o$ and a torus with electrically neutral mass $m_m$ in the middle, whereas the star bears a charge $Q_s$ ($Q_o$ and $Q_s$ have the same sign, $Q_i$ the opposite one). The frequency $\nu_m$ of the mass current is approximately given by the Kepler frequency, whereas the frequencies of $Q_i$ and $Q_o$, $\nu_i$ and $\nu_o$, respectively, are calculated from classical mechanics and Coulomb's law. For the explanation of the low frequency QPOs in pulsars and black holes a special interpretation of the gravitomagnetic theory may be essential. From the latter theory four new gravitomagnetic precession frequencies are deduced, which may be identified with the observed low frequency QPOs. Predictions of the presented model are compared with observed high frequency and low frequency QPOs of the pulsars SAX J1808.4--3658, XTE J1807--294, IGR J00291+5934, SGR 1806--20 and the black hole XTE J1550--564. In addition, charge flow near the pole of pulsars may explain frequency drift of burst oscillations. Moreover, charge flow at the equator of SAX J1808.4--3658 may be the cause of the enigmatic 410 kHz QPO. Furthermore, the Lense-Thirring frequency is discussed and a modified formula is compared with data of the pulsars. Contrary to pulsars and black holes, the low frequency QPOs of white dwarfs might be attributed to electromagnetic precession frequencies, deduced in this work. Predictions are compared with data of the dwarf nova VW Hyi.