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 . 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 the spectra indicate a very slow cooling by 2 eV over 7 years.
Keywords
Cite
@article{arxiv.1203.3708,
title = {The continued spectral and temporal evolution of RX J0720.4-3125},
author = {Markus M. Hohle and Frank Haberl and Jacco Vink and Cor P. de Vries and Roberto Turolla and Silvia Zane and Mariano Méndez},
journal= {arXiv preprint arXiv:1203.3708},
year = {2015}
}
Comments
seven pages, three figures, three tables; accepted by MNRAS