Evidence for precession of the isolated neutron star RX J0720.4-3125

Abstract

The XMM-Newton spectra of the isolated neutron star RX J0720.4-3125 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 RX J0720.4-3125. 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.

arXiv commentAccepted for publication in A&A Letters, 5 pages, 5 figures

References in corpus (19)

• Freely precessing neutron stars: Model and observations
• Isolated Neutron Stars: Accretors and Coolers
• The proper motion and energy distribution of the isolated neutron star RX J0720.4-3125
• A broad absorption feature in the X-ray spectrum of the isolated neutron star RBS1223 (1RXS J130848.6+212708)
• A Strong, Broad Absorption Feature in the X-ray Spectrum of the Nearby Neutron Star RX J1605.3+3249
• Precession of the Isolated Neutron Star PSR B1828-11
• Unveiling the thermal and magnetic map of neutron star surfaces though their X-ray emission: method and lightcurves analysis
• A phase-dependent absorption line in the spectrum of the X-ray pulsar RX J0720.4-3125
• The Nearby Neutron Star RX J0720.4-3125 from Radio to X-rays
• A Coherent Timing Solution for the Nearby Isolated Neutron Star RX J0720.4-3125
• Detection of pulsations and a spectral feature in the X-ray emission of the isolated neutron star 1RXS J214303.7+065419/RBS 1774
• A Coherent Timing Solution for the Nearby Isolated Neutron Star RX J1308.6+2127/RBS 1223
• Optical Observations of the Isolated Neutron Star RX J0720.4-3125
• Timing analysis of the isolated neutron star RX J0720.4-3125
• Long-term variability in the X-ray emission of RX J0720.4-3125
• AXPs and X-ray dim neutron stars: Recent XMM-Newton and Chandra results
• The pulsed X-ray light curves of the isolated neutron star RBS1223
• Timing Analysis of the Isolated Neutron Star RX J0720.4-3125 Revisited
• Isolated neutron stars discovered by ROSAT

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