Modelling of the surface emission of the low magnetic field magnetar SGR 0418+5729

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dc.contributor.authorGuillot, S.
dc.contributor.authorPerna, R.
dc.contributor.authorRea, N.
dc.contributor.authorVigano, D.
dc.contributor.authorPons, J. A.
dc.date.accessioned2025-01-23T21:34:02Z
dc.date.available2025-01-23T21:34:02Z
dc.date.issued2015
dc.description.abstractWe perform a detailed modelling of the post-outburst surface emission of the low magnetic field magnetar SGR 0418+5729. The dipolar magnetic field of this source, B = 6 x 10(12) G estimated from its spin-down rate, is in the observed range of magnetic fields for normal pulsars. The source is further characterized by a high pulse fraction and a single-peak profile. Using synthetic temperature distribution profiles, and fully accounting for the general-relativistic effects of light deflection and gravitational redshift, we generate synthetic X-ray spectra and pulse profiles that we fit to the observations. We find that asymmetric and symmetric surface temperature distributions can reproduce equally well the observed pulse profiles and spectra of SGR 0418. None the less, the modelling allows us to place constraints on the system geometry (i.e. the angles. and. that the rotation axis makes with the line of sight and the dipolar axis, respectively), as well as on the spot size and temperature contrast on the neutron star surface. After performing an analysis iterating between the pulse profile and spectra, as done in similar previous works, we further employed, for the first time in this context, a Markov-Chain Monte Carlo approach to extract constraints on the model parameters from the pulse profiles and spectra, simultaneously. We find that, to reproduce the observed spectrum and flux modulation: (a) the angles must be restricted to 65 degrees less than or similar to psi + xi less than or similar to 125 degrees or 235 degrees less than or similar to psi + xi less than or similar to 295 degrees; (b) the temperature contrast between the poles and the equator must be at least a factor of similar to 6, and (c) the size of the hottest region ranges between 0.2 and 0.7 km (including uncertainties on the source distance). Lastly, we interpret our findings within the context of internal and external heating models.
dc.fuente.origenWOS
dc.identifier.doi10.1093/mnras/stv1535
dc.identifier.eissn1365-2966
dc.identifier.issn0035-8711
dc.identifier.urihttps://doi.org/10.1093/mnras/stv1535
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/101527
dc.identifier.wosidWOS:000360862100007
dc.issue.numero4
dc.language.isoen
dc.pagina.final3368
dc.pagina.inicio3357
dc.revistaMonthly notices of the royal astronomical society
dc.rightsacceso restringido
dc.subjectstars: magnetars
dc.subjectpulsars: general
dc.subjectX-rays: individual: SGR 0418+5729
dc.titleModelling of the surface emission of the low magnetic field magnetar SGR 0418+5729
dc.typeartículo
dc.volumen452
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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