Jet-driven explosion of an accretion-induced white-dwarf collapse via a magnetorotational dynamo
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arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| author | Combi, Luciano Siegel, Daniel M. Metzger, Brian D. |
| author_facet | Combi, Luciano Siegel, Daniel M. Metzger, Brian D. |
| contents | The accretion-induced collapse (AIC) of a rotating white dwarf (WD) offers a potential site of millisecond pulsars/magnetars, gamma-ray bursts, and r-process nucleosynthesis. We present three-dimensional general-relativistic magneto-hydrodynamical simulations including neutrinos of magnetorotational AIC, assuming the WD is rapidly spinning with a weak magnetic field confined below its surface (likely a prerequisite for rapid rotation). Within milliseconds after core bounce, the magnetic field is exponentially amplified near the surface of the proto-neutron star (PNS). We witness the emergence of a small-scale turbulent and mean-field, large-scale MRI-driven dynamo in the neutrino-cooled centrifugally supported disk formed around the PNS, which generates bundles of large-scale toroidal field with alternating polarity. The amplified field becomes buoyant and is advected above the PNS, generating a magnetic tower that drives a mildly relativistic striped jet. The jet breaks out of the WD, clearing the way for a powerful magnetized neutron-rich wind from the disk. Although our simulation cannot follow the long-term Kelvin-Helmholtz cooling phase of the PNS, the conditions are ripe for the formation of a GRB powered by magnetar spin-down. A similar dynamo may operate in magnetorotational core-collapse supernovae and neutron-star mergers. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_19799 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Jet-driven explosion of an accretion-induced white-dwarf collapse via a magnetorotational dynamo Combi, Luciano Siegel, Daniel M. Metzger, Brian D. High Energy Astrophysical Phenomena General Relativity and Quantum Cosmology The accretion-induced collapse (AIC) of a rotating white dwarf (WD) offers a potential site of millisecond pulsars/magnetars, gamma-ray bursts, and r-process nucleosynthesis. We present three-dimensional general-relativistic magneto-hydrodynamical simulations including neutrinos of magnetorotational AIC, assuming the WD is rapidly spinning with a weak magnetic field confined below its surface (likely a prerequisite for rapid rotation). Within milliseconds after core bounce, the magnetic field is exponentially amplified near the surface of the proto-neutron star (PNS). We witness the emergence of a small-scale turbulent and mean-field, large-scale MRI-driven dynamo in the neutrino-cooled centrifugally supported disk formed around the PNS, which generates bundles of large-scale toroidal field with alternating polarity. The amplified field becomes buoyant and is advected above the PNS, generating a magnetic tower that drives a mildly relativistic striped jet. The jet breaks out of the WD, clearing the way for a powerful magnetized neutron-rich wind from the disk. Although our simulation cannot follow the long-term Kelvin-Helmholtz cooling phase of the PNS, the conditions are ripe for the formation of a GRB powered by magnetar spin-down. A similar dynamo may operate in magnetorotational core-collapse supernovae and neutron-star mergers. |
| title | Jet-driven explosion of an accretion-induced white-dwarf collapse via a magnetorotational dynamo |
| topic | High Energy Astrophysical Phenomena General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2509.19799 |