Borghese, A;
Rea, N;
Zelati, FC;
Turolla, R;
Tiengo, A;
Zane, S;
(2017)
Phase-dependent absorption features in X-ray spectra of X-ray Dim Isolated Neutron Stars.
In:
(Proceedings) International Conference Physics of Neutron Stars.
(pp. 012007-012007).
IOP Publishing
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Abstract
A detailed phase-resolved spectroscopy of archival XMM-Newton observations of X-ray Dim Isolated Neutron Stars (XDINSs) led to the discovery of narrow and strongly phase-dependent absorption features in two of these sources. The first was discovered in the X-ray spectrum of RX J0720.4-3125, followed by a new possible candidate in RX J1308.6+2127. Both spectral lines have similar properties: they are detected for only ∼ 20% of the rotational cycle and appear to be stable over the timespan covered by the observations. We performed Monte Carlo simulations to test the significance of these phase-variable features and in both cases the outcome has confirmed the detection with a confidence level > 4.6σ. Because of the narrow width and the strong dependence on the pulsar rotational phase, the most likely interpretation for these spectral features is in terms of resonant proton cyclotron absorption scattering in a confined high-B structure close to the stellar surface. Within the framework of this interpretation, our results provide evidence for deviations from a pure dipole magnetic field on small scales for highly magnetized neutron stars and support the proposed scenario of XDINSs being aged magnetars, with a strong non-dipolar crustal B-field component.
| Type: | Proceedings paper |
|---|---|
| Title: | Phase-dependent absorption features in X-ray spectra of X-ray Dim Isolated Neutron Stars |
| Event: | International Conference Physics of Neutron Stars |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1088/1742-6596/932/1/012007 |
| Publisher version: | https://doi.org/10.1088/1742-6596/932/1/012007 |
| Language: | English |
| Additional information: | Content from this work may be used under the terms of theCreative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10041339 |
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