The continued spectral and temporal evolution of RX J0720.4-3125

Abstract

RX J0720.4-3125 is the most peculiar object among a group of seven isolated X-ray pulsars (the so-called "Magnificent Seven"), since it shows long-term variations of its spectral and temporal properties on time scales of years. This behaviour was explained by different authors either by free precession (with a seven or fourteen years period) or possibly a glitch that occurred around $\mathrm{MJD}=52866\pm 73days$. We analysed our most recent XMM-Newton and Chandra observations in order to further monitor the behaviour of this neutron star. With the new data sets, the timing behaviour of RX J0720.4-3125 suggests a single (sudden) event (e.g. a glitch) rather than a cyclic pattern as expected by free precession. The spectral parameters changed significantly around the proposed glitch time, but more gradual variations occurred already before the (putative) event. Since $\mathrm{MJD}\approx 53000days$ the spectra indicate a very slow cooling by $\sim$2 eV over 7 years.

seven pages, three figures, three tables; accepted by MNRAS

References in corpus (6)

• The Magnificent Seven: Magnetic fields and surface temperature distributions
• Evidence for precession of the isolated neutron star RX J0720.4-3125
• Is SGR 0418+5729 indeed a waning magnetar ?
• Constraining the Spin-down of the Nearby Isolated Neutron Star RX J2143.0+0654
• Narrow absorption features in the co-added XMM-Newton RGS spectra of isolated Neutron Stars
• XMM-Newton RGS spectrum of RX J0720.4-3125: An absorption feature at 0.57 keV

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• Hard X-ray Excess from the Magnificent Seven Neutron Stars
• Universal detection of high-temperature emission in X-ray Isolated Neutron Stars
• Two decades of X-ray observations of the isolated neutron star RX J1856.5-3754: detection of thermal and non-thermal hard X-rays and refined spin-down measurement
• Probing the surface magnetic field structure in RX J1856.5-3754
• Herschel and Spitzer observations of slowly rotating, nearby isolated neutron stars
• X-ray and near-infrared observations of the middle-aged pulsar B1055-52, its multiwavelength spectrum, and proper motion
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