A connection between proto-neutron-star Tayler–Spruit dynamos and low-field magnetars
Low-field magnetars have dipolar magnetic fields of 10<sup>12</sup>-10<sup>13</sup> G, 10-100 times weaker than the values of magnetic-field strength <i>B</i> ≈ 10<sup>14</sup>-10<sup>15</sup> G used to define classical magnetars, yet they produce similar X-ray bursts and outbursts. Using direct numerical simulations of magnetothermal evolution starting from a dynamo-generated magnetic field, we show that the low-field magnetars can be produced as a result of a Tayler-Spruit dynamo inside a proto-neutron star. We find that these simulations naturally explain key characteristics of low-field magnetars: weak (≲10<sup>13</sup> G) dipolar magnetic fields, strong small-scale fields and magnetically induced crustal failures producing X-ray bursts. These findings suggest that the formation channel of low-<i>B</i> magnetars is distinct from that for classical magnetars, reflecting potential differences in proto-neutron-star dynamos.
Authors
- Jérôme Guilet (ORCID: https://orcid.org/0000-0002-7518-8752)
- Toby S. Wood (ORCID: https://orcid.org/0000-0003-1044-170X)
- Paul Barrère (ORCID: https://orcid.org/0000-0002-4441-5625)
- R Raynaud (ORCID: https://orcid.org/0000-0001-6815-7109)
- Andrei P. Igoshev (ORCID: https://orcid.org/0000-0003-2145-1022)
- Rainer Hollerbach (ORCID: https://orcid.org/0000-0001-8639-0967)
Institutions
- University of Geneva (CH)
- Centre National de la Recherche Scientifique (FR)
- University of Leeds (GB)
- Université Paris Cité (FR)
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR)
- Université Paris-Saclay (FR)
- Astrophysique, Instrumentation et Modélisation (FR)
- CEA Paris-Saclay (FR)
- Newcastle University (GB)
Publication Details
- Journal
- Nature Astronomy
- Published
- 2025-02-04
- DOI
- https://doi.org/10.1038/s41550-025-02477-y
- Citations
- 6
- Primary Topic
- Pulsars and Gravitational Waves Research
- Type
- article
- Field-Weighted Citation Impact
- 6.93
Funders
- University of Leicester
- Centre National d’Etudes Spatiales
- Centre National de la Recherche Scientifique
- Science and Technology Facilities Council
- Division of Mathematical Sciences