Journal article
Thermal luminosity degeneracy of magnetized neutron stars with and without hyperon cores
F Anzuini, A Melatos, C Dehman, D Viganò, JA Pons
Monthly Notices of the Royal Astronomical Society | Published : 2022
Abstract
The dissipation of intense crustal electric currents produces high Joule heating rates in cooling neutron stars. Here, it is shown that Joule heating can counterbalance fast cooling, making it difficult to infer the presence of hyperons (which accelerate cooling) from measurements of the observed thermal luminosity Lγ. Models with and without hyperon cores match Lγ of young magnetars (with poloidal-dipolar field Bdip ≳ 1014 G at the polar surface and Lγ ≳ 1034 erg s-1 at t ≲ 105 yr) as well as mature, moderately magnetized stars (with Bdip ≲ 1014 G and 1031 erg s-1 ≲ Lγ ≲ 1032 erg s-1 at t ≳ 105 yr). In magnetars, the crustal temperature is almost independent of hyperon direct Urca cooling i..
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Grants
Awarded by Horizon 2020 Framework Programme
Funding Acknowledgements
We thank Prof. Xavier Vinas and Prof. Mario Centelles for providing the BCPM nuclear energy density functional used to test the in medium correction factors for the modified Urca emissivity. FA is supported by The University of Melbourne through a Melbourne Research Scholarship. AM acknowledges funding from an Australian Research Council Discovery Project grant (DP170103625) and the Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav) (CE170100004). DV is supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (ERC Starting Grant 'IMAGINE' No. 948582, PI DV). CD is supported by the ERC Consolidator Grant 'MAGNESIA' (No. 817661, PI: Nanda Rea) and this work has been carried out within the framework of the doctoral programme in Physics of the Universitat Autnoma de Barcelona. JAP acknowledges support by the Generalitat Valenciana (PROMETEO/2019/071), AEI grant PGC2018-095984-B-I00, and the Alexander von Humboldt Stiftung through a Humboldt Research Award.