Numerical Study on the Rotational Collapse of Strongly Magnetized Cores of Massive Stars

Yamada, Shoichi; Sawai, Hidetomo

doi:10.1086/420760

Cited by 77 publications

(99 citation statements)

References 40 publications

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“…As we mention below, these studies are complimentary in the sense that the different epochs are focused on, with the different initial conditions for the numerical modeling being taken. In addition to the elaborate studies in the conventional supernova context (see recent reviews for Kotake et al 2006;Janka et al 2007), much attention has been paid recently to the roles of rapid rotation and magnetic fields for studying the formation of magnetars and its possible application to the collapsars (Yamada & Sawai 2004;Takiwaki et al 2004;Kotake et al 2004b;Sawai et al 2005;Matt et al 2006;Moiseenko et al 2006;Obergaulinger et al 2006;Nishimura et al 2006;Burrows et al 2007;Cerdá-Durán et al 2007;Scheidegger et al 2007;Komissarov & Barkov 2007). After the failed or weak explosion, the accretion to the central objects may lead to the formation of a BH (phase 2).…”

Section: No 2 2009 Srmhd Simulations Of Magnetically Dominated Jetsmentioning

confidence: 99%

Special Relativistic Simulations of Magnetically Dominated Jets in Collapsing Massive Stars

Takiwaki

Kotake

Sato

2009

ApJ

168

174

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We perform a series of two-dimensional magnetohydrodynamic core-collapse simulations of rapidly rotating and strongly magnetized massive stars. To study the properties of magnetic explosions for a longer time stretch of postbounce evolution, we develop a new code under the framework of special relativity including a realistic equation of state with a multiflavor neutrino leakage scheme. Our results show the generation of the magnetically dominated jets in the two ways. One is launched just after the core bounce in a prompt way and another is launched at ∼ 100 ms after the stall of the prompt shock. We find that the shock-revival occurs when the magnetic pressure becomes strong enough, due to the field wrapping, to overwhelm the ram pressure of the accreting matter. The critical toroidal magnetic fields for the magnetic shock-revival are found to be universal of ∼ 10 15 G behind the jets. We point out that the time difference before the shock-revival has a strong correlation with the explosion energies. Our results suggest that the magnetically dominated jets are accompanied by the formation of the magnetars. Since the jets are mildly relativistic, we speculate that they might be the origin of some observed X-ray flashes.

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Section: No 2 2009 Srmhd Simulations Of Magnetically Dominated Jetsmentioning

confidence: 99%

Special Relativistic Simulations of Magnetically Dominated Jets in Collapsing Massive Stars

Takiwaki

Kotake

Sato

2009

ApJ

168

174

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“…Core-collapse supernovae (CC-SNe) driven by rotation and magnetic fields, so-called magneto-rotational supernovae (MR-SNe), are a promising mechanism for several high-energy astronomical phenomena, e.g., magnetar formation, gravitational waves and hypernovae, and gamma-ray bursts (e.g., Yamada & Sawai 2004;Shibata et al 2006;Takiwaki et al 2009;Mösta et al 2014). Jet-like explosions in CCSNe are expected to eject very neutron-rich matter, appropriate for the r-process (e.g., Cameron 2003;Papish & Soker 2012).…”

Section: Introductionmentioning

confidence: 99%

The Intermediate r-process in Core-collapse Supernovae Driven by the Magneto-rotational Instability

Nishimura

Sawai

Takiwaki

et al. 2017

ApJL

177

197

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We investigated r-process nucleosynthesis in magneto-rotational supernovae, based on a new explosion mechanism induced by the magneto-rotational instability (MRI). A series of axisymmetric magnetohydrodynamical simulations with detailed microphysics including neutrino heating is performed, numerically resolving the MRI. Neutrino-heating dominated explosions, enhanced by magnetic fields, showed mildly neutronrich ejecta producing nuclei up toÃ 130 (i.e., the weak r-process), while explosion models with stronger magnetic fields reproduce a solar-like r-process pattern. More commonly seen abundance patterns in our models are in between the weak and regular r-process, producing lighter and intermediate-mass nuclei. These intermediate r-processes exhibit a variety of abundance distributions, compatible with several abundance patterns in r-processenhanced metal-poor stars. The amount of Eu ejectain magnetically driven jets agrees with predicted values in the chemical evolution of early galaxies. In contrast, neutrino-heating dominated explosions have a significant amount of Fe ( Ni 56 ) and Zn, comparable to regular supernovae and hypernovae, respectively. These results indicate magneto-rotational supernovae can produce a wide range of heavy nuclei from iron-group to r-process elements, depending on the explosion dynamics.

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“…However, most studies of the past thirty years were either concerned with the collapse and bounce signal only (Müller 1982;Finn & Evans 1990;Mönchmeyer et al 1991;Yamada & Sato 1994;Zwerger & Müller 1997;Rampp et al 1998;Dimmelmeier et al 2001Dimmelmeier et al , 2002Kotake et al 2003;Shibata 2003;Shibata & Sekiguchi 2004;Ott et al 2004;Cerda-Duran et al 2005;Saijo 2005;Shibata & Sekiguchi 2005;Kotake et al 2006;Dimmelmeier et al 2007;Ott et al 2007;Dimmelmeier et al 2008), or were A&A 537, A63 (2012) restricted to axisymmetric (2D) models (Müller et al 2004;Ott et al 2006;Kotake et al 2007;Murphy et al 2009;Yakunin et al 2010). Several authors also investigated the influence of magnetic fields on the GW signal during the collapse and early post-bounce evolution assuming axisymmetry (Kotake et al 2004;Yamada & Sawai 2004;Kotake et al 2005;Obergaulinger et al 2006a,b) and no symmetry restriction at all (Scheidegger et al 2008(Scheidegger et al , 2010. The GW signal caused by aspherical neutrino emission was first studied by Epstein (1978) and subsequently by Burrows & Hayes (1996), Müller & Janka (1997), and Kotake et al (2007Kotake et al ( , 2009aKotake et al ( ,b, 2011, where the investigations by …”

Section: Introductionmentioning

confidence: 99%

Parametrized 3D models of neutrino-driven supernova explosions

Müller

Janka

Wongwathanarat

2012

A&A

113

144

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Time-dependent and direction-dependent neutrino and gravitational-wave (GW) signatures are presented for a set of three-dimensional (3D) hydrodynamic models of parametrized, neutrino-driven supernova explosions of non-rotating 15 and 20 M stars. We employed an approximate treatment of neutrino transport based on a gray spectral description and a ray-by-ray treatment of multi-dimensional effects. Owing to the excision of the high-density core of the proto-neutron star (PNS) and the use of an axis-free (Yin-Yang) overset grid, the models can be followed from the post-bounce accretion phase through the onset of the explosion into more than one second of the early cooling evolution of the PNS without imposing any symmetry restrictions and covering a full sphere. Gravitational waves and neutrino emission exhibit the generic time-dependent features already known from 2D (axi-symmetric) models. Violent non-radial hydrodynamic mass motions in the accretion layer and their interaction with the outer layers of the proto-neutron star together with anisotropic neutrino emission give rise to a GW signal with an amplitude of ∼5−20 cm in the frequency range of 100−500 Hz. The GW emission from mass motions usually reaches a maximum before the explosion sets in. After the onset of the explosion the GW signal exhibits a low-frequency modulation, in some cases describing a quasi-monotonic growth, associated with the non-spherical expansion of the explosion shock wave and the large-scale anisotropy of the escaping neutrino flow. Variations of the mass-quadrupole moment caused by convective activity inside the nascent neutron star add a high-frequency component to the GW signal during the post-explosion phase. The GW signals exhibit strong variability between the two polarizations, different explosion simulations and different observer directions, and besides common basic features do not possess any template character. The neutrino emission properties (fluxes and effective spectral temperatures) show fluctuations over the neutron star surface on spatial and temporal scales that reflect the different types of non-spherical mass motions in the supernova core, i.e., post-shock overturn flows and proto-neutron star convection. However, because very prominent, quasi-periodic sloshing motions of the shock caused by the standing accretion-shock instability are absent and the emission from different surface areas facing an observer adds up incoherently, the modulation amplitudes of the measurable neutrino luminosities and mean energies are significantly lower than predicted by 2D simulations.

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Numerical Study on the Rotational Collapse of Strongly Magnetized Cores of Massive Stars

Cited by 77 publications

References 40 publications

Special Relativistic Simulations of Magnetically Dominated Jets in Collapsing Massive Stars

Special Relativistic Simulations of Magnetically Dominated Jets in Collapsing Massive Stars

The Intermediate r-process in Core-collapse Supernovae Driven by the Magneto-rotational Instability

Parametrized 3D models of neutrino-driven supernova explosions

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