Core collapse with magnetic fields and rotation

Obergaulinger, M.; Just, Oliver; Aloy, M. Á.

doi:10.1088/1361-6471/aac982

Cited by 58 publications

(59 citation statements)

References 67 publications

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“…4). If a magnetar is born with a sufficiently strong, tangled magnetic field, predicted to occur under some circumstances following core-collapse (Obergaulinger & Aloy 2017;Obergaulinger et al 2018) and NS-NS merger events Ciolfi et al 2019), the Hall time (3) can be sufficiently short so as to instigate rapid field evolution in the crust over 10 2 yr [in agreement with the predicted age of the object within FRB 121102 (Bower et , generating magnetic stresses which crack the crust and release energy. We find that a multipolar magnetic field is important in the scenario because it allows for multiple, isolated fractures, each of which contribute separately to the overall burst activity, alleviating the concerns of Li et al (2019) concerning the waiting time statistics of FRB 121102.…”

Section: Discussionmentioning

confidence: 99%

Young magnetars with fracturing crusts as fast radio burst repeaters

Suvorov

Kokkotas

2019

Monthly Notices of the Royal Astronomical Society

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Fast radio bursts are millisecond-duration radio pulses of extragalactic origin. A recent statistical analysis has found that the burst energetics of the repeating source FRB 121102 follow a power-law, with an exponent that is curiously consistent with the Gutenberg-Richter law for earthquakes. This hints that repeat-bursters may be compact objects undergoing violent tectonic activity. For young magnetars, possessing crustal magnetic fields which are both strong (B 10 15 G) and highly multipolar, Hall drift can instigate significant field rearrangements even on century long timescales. This reconfiguration generates zones of magnetic stress throughout the outer layers of the star, potentially strong enough to facilitate frequent crustal failures. In this paper, assuming a quake scenario, we show how the crustal field evolution, which determines the resulting fracture geometries, can be tied to burst properties. Highly anisotropic stresses are generated by the rapid evolution of multipolar fields, implying that small, localised cracks can occur sporadically throughout the crust during the Hall evolution. Each of these shallow fractures may release bursts of energy, consistent in magnitude with those seen in the repeating sources FRB 121102 and FRB 180814.J0422+73.

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Section: Discussionmentioning

confidence: 99%

Young magnetars with fracturing crusts as fast radio burst repeaters

Suvorov

Kokkotas

2019

Monthly Notices of the Royal Astronomical Society

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“…We perform our axysimmetric simulations using the numerical code AENUS-ALCAR (Obergaulinger et al 2014b;Just et al 2015), which solves the equations of special-relativistic magnetohydrodynamic (SRMHD) coupled to a M1 closure scheme for the neutrino transport in an approximated Newtonian gravitational potential with relativistic corrections. Since the code has been employed in the last decade for several studies on magnetised CCSN (Obergaulinger et al 2006a(Obergaulinger et al , 2014aObergaulinger et al 2018), we will make use of an initial setup very similar to the model 35OC-Rs presented in Obergaulinger & Aloy (2017a), which essentially differs just for the magnetic field considered.…”

Section: Modelsmentioning

confidence: 99%

“…For the latter, we assume a composition of pure 28 Si for temperatures T < 0.44 MeV or pure 56 Ni otherwise. The interaction processes between matter and neutrinos that we consider include nucleonic and nuclear scattering and absorption, inelastic scattering of electrons, electron-positron annihilation into pairs of neutrinos and anti-neutrinos and nucleon-nucleon bremsstrahlung (for a complete list see Obergaulinger et al 2018).…”

Section: Numerical Setupmentioning

confidence: 99%

“…Whether we consider a pre-existing magnetic field in the progenitor or one resulting from dynamics in the PNS, the topology and spatial distribution of the field lines is even less constrained than the field strength. A common initial setup used in magnetised corecollapse simulations employs a dipolar-like magnetic field superimposed on a hydrodynamic background (usually provided by stellar evolution models), with the field having a more or less constant strength up to a characteristic radius r 0 and then decaying as ∼ r −3 (Suwa et al 2007;Burrows et al 2007;Takiwaki et al 2009;Mösta et al 2014;Obergaulinger et al 2014a;Obergaulinger & Aloy 2017a;Mösta et al 2018;Obergaulinger et al 2018;. This magnetic field configuration is chosen for the sake of simplicity but is most probably not realistic.…”

Section: Introductionmentioning

confidence: 99%

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The impact of non-dipolar magnetic fields in core-collapse supernovae

Bugli

Guilet

Obergaulinger

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The magnetic field is believed to play an important role in at least some core-collapse supernovae if its magnitude reaches10 15 G, which is a typical value for a magnetar. In the presence of fast rotation, such a strong magnetic field can drive powerful jet-like explosions if it has the large-scale coherence of a dipole. The topology of the magnetic field is, however, probably much more complex with strong multipolar and small-scale components and the consequences for the explosion are so far unclear. We investigate the effects of the magnetic field topology on the dynamics of core-collapse supernovae and the properties of forming proto-neutron star (PNS) by comparing pre-collapse fields of different multipolar orders and radial profiles. Using axisymmetric special relativistic MHD simulations and a two-moment neutrino transport, we find that higher multipolar magnetic configurations lead to generally less energetic explosions, slower expanding shocks and less collimated outflows. Models with a low order multipolar configuration tend to produce more oblate PNS, surrounded in some cases by a rotationally supported toroidal structure of neutron-rich material. Moreover, magnetic fields which are distributed on smaller angular scales produce more massive and faster rotating central PNS, suggesting that higher order multipolar configurations tend to decrease the efficiency of the magnetorotational launching mechanism. Even if our dipolar models systematically display a far more efficient extraction of the rotational energy of the PNS, fields distributed on smaller angular scales are still capable of powering magnetorotational explosions and shape the evolution of the central compact object.

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“…Ref. [11][12][13]). However, a generation of such a strong magnetic field is also possible without the fast rotation of the supernova core [14].…”

Section: Introductionmentioning

confidence: 99%

Influence of a magnetic field on beta-processes in supernova matter

Dobrynina

Ognev

2020

Phys. Rev. D

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An influence of a magnetic field on beta-processes is investigated under conditions of a corecollapse supernova. For realistic magnetic fields reachable in astrophysical objects we obtain simple analytical expressions for reaction rates of beta-processes as well as the energy and momentum transferred from neutrinos and antineutrinos to the matter. Based on the results of one-dimensional simulations of a supernova explosion, we found that, in the magnetic field with the strength ∼ 10 15 G, the quantities considered are modified by several percents only and, as a consequence, the magnetic-field effects can be safely neglected, considering neutrino interaction and propagation in a supernova matter. The analytical results can be also applied for accretion discs formed at a merger of compact objects in close binary systems.

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Core collapse with magnetic fields and rotation

Cited by 58 publications

References 67 publications

Young magnetars with fracturing crusts as fast radio burst repeaters

Young magnetars with fracturing crusts as fast radio burst repeaters

The impact of non-dipolar magnetic fields in core-collapse supernovae

Influence of a magnetic field on beta-processes in supernova matter

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