Abstract
The XMM-Newton spectra of the isolated neutron star RXJ0720.4−3125 obtained over 4.5 years can be described by sinusoidal variations in
the inferred blackbody temperature, the size of the emitting area and the depth of the absorption line with a period of 7.1 ± 0.5 years, which
we suggest to be the precession period of the neutron star. Precession of a neutron star with two hot spots of different temperature and size,
probably not located exactly in antipodal positions, may account for the variations in the X-ray spectra, changes in the pulsed fraction, shape
of the light curve and the phase-lag between soft and hard energy bands observed from RXJ0720.4−3125. An independent sinusoidal fit to
published and new pulse timing residuals from a coherent analysis covering ∼12 years yields a consistent period of 7.7 ± 0.6 years supporting
the precession model.
| Original language | Undefined/Unknown |
|---|---|
| Pages (from-to) | L17-L21 |
| Number of pages | 5 |
| Journal | Astronomy and Astrophysics |
| Volume | 451 |
| Issue number | 2 |
| Publication status | Published - 2006 |