Towards self-consistent models of isolated neutron stars |
| |
| Authors: | J A Pons J F Pérez-Azorín J A Miralles G Miniutti |
| |
| Institution: | (1) Departament de Física Aplicada, Universitat d’Alacant, Ap. Correus 99, 03080 Alacant, Spain;(2) Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK |
| |
| Abstract: | We propose a self–consistent model to explain all observational properties reported so far on the isolated neutron star (INS)
RX J0720-3125 with the aim of giving a step forward towards our understanding of INSs. For a given magnetic field structure,
which is mostly confined to the crust and outer layers, we obtain theoretical models and spectra which account for the broadband
spectral energy distribution (including the apparent optical excess), the X-ray pulsations, and for the spectral feature seen
in the soft X-ray spectrum of RX J0720-3125 around 0.3 keV. By fitting our models to existing archival X-ray data from 6 different
XMM–Newton observations and available optical data, we show that the observed properties are fully consistent with a normal neutron star, with a proper radius of about 12 km, a temperature at the magnetic pole of about 100 eV, and a magnetic field
strength of 2–3×1013 G. Moreover, we are able to reproduce the observed long–term spectral evolution in terms of free precession which induces
changes in the orientation angles of about 40 degrees with a periodicity of 7 years. In addition to the evidence of internal
toroidal components, we also find strong evidence of non–dipolar magnetic fields, since all spectral properties are better
reproduced with models with strong quadrupolar components.
|
| |
| Keywords: | Stars: neutron Stars: magnetic fields Radiation mechanisms: thermal |
| 本文献已被 SpringerLink 等数据库收录！ |
|
