Quasi-Periodic Oscillations of GRO J1744-28

Authors: Jacob Biemond

Observed quasi-periodic oscillations (QPOs) of GRO J1744-28 are compared with predictions from a previously proposed three tori model. The three highest QPO frequencies are assumed to arise from three circular tori moving around the pulsar: an inner torus with charge Qi, a torus with mass mm in the middle and an outer torus with charge Qo, whereas the pulsar itself bears a charge Qs.

In addition, it follows from a special interpretation of the gravitomagnetic theory, that the three circular tori are subjected to a total number of four low-frequency precessions. The expressions of these four additional QPO frequencies are revised compared to earlier work. For GRO J1744-28 the two lowest observed QPO frequencies are attributed to the two highest of the four low-frequency QPOs. The two other frequencies of the quartet may be too low to be detected. From the two highest QPO frequencies of the quartet, lying close together, approximate values for the charges Qs, Qi, and Qo are extracted. The results are compared with the observed and predicted set of seven QPOs for five other pulsars and two black holes.

The observed magnetic field is compared with the polar magnetic field, also predicted by the gravitomagnetic theory. Remarkably, the observed highly ionized iron emission lines may be compatible with the tree tori model. In order to explain the discontinuity in recently observed phase lags of GRO J1744-28, a Compton reverberation mechanism is considered, compatible with electron temperatures that depend on the radii of the tori.

Comments: 14 Pages, including 1 table

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Submission history

[v1] 2017-02-22 14:27:53

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