SELF-SUSTAINED ASYMMETRY OF LEPTON-NUMBER EMISSION: A NEW PHENOMENON DURING THE SUPERNOVA SHOCK-ACCRETION PHASE IN THREE DIMENSIONS

By I. Tamborra, Florian Hanke, Hans-Thomas Janka, B. Mueller, G. Raffelt, Andreas Marek. 2014

160 citations recorded by the source corpus.

During the stalled-shock phase of our three-dimensional, hydrodynamical core-collapse simulations with energy-dependent, three-flavor neutrino transport, the lepton-number flux (νe minus ) emerges predominantly in one hemisphere. This novel, spherical-symmetry breaking neutrino-hydrodynamical instability is termed LESA for “Lepton-number Emission Self-sustained Asymmetry.” While the individual νe and fluxes show a pronounced dipole pattern, the heavy-flavor neutrino fluxes and the overall luminosity are almost spherically symmetric. Initially, LESA seems to develop stochastically from convective fluctuations. It exists for hundreds of milliseconds or more and persists during violent shock sloshing associated with the standing accretion shock instability. The νe minus flux asymmetry originates predominantly below the neutrinosphere in a region of pronounced proto-neutron star (PNS) convection, which is stronger in the hemisphere of enhanced lepton-number flux. On this side of the PNS, the mass accretion rate of lepton-rich matter is larger, amplifying the lepton-emission asymmetry, because the spherical stellar infall deflects on a dipolar deformation of the stalled shock. The increased shock radius in the hemisphere of less mass accretion and minimal lepton-number flux ( flux maximum) is sustained by stronger convection on this side, which is boosted by stronger neutrino heating due to . Asymmetric heating thus supports the global deformation despite extremely nonstationary convective overturn behind the shock. While these different elements of the LESA phenomenon form a consistent picture, a full understanding remains elusive at present. There may be important implications for neutrino-flavor oscillations, the neutron-to-proton ratio in the neutrino-heated supernova ejecta, and neutron-star kicks, which remain to be explored.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/8c034c060e2c28384daf9f95de20920d270ad5d3

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Citations in the corpus

Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume II: DUNE Physics (2020, background): “Neutrino emission from the supernova may furthermore have an emitted lepton-flavor asymmetry [257], so that observed rates may be dependent on the supernova direction.”
Neutron Star Kicks by the Gravitational Tug-boat Mechanism in Asymmetric Supernova Explosions: Progenitor and Explosion Dependence (2016, background): “Estimates of the NS kick velocity associated with the LESA asymmetry by Tamborra et al. (2014a) are, however, considerably lower than 100 km s−1.”
Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF (2015, background): “Furthermore, neutrino emission from the supernova may exhibit an emitted lepton-flavor asymmetry [127], which would lead to observed rates being direction-dependent.”
The Status of Multi-Dimensional Core-Collapse Supernova Models (2016, background): “…based on multi-group neutrino transport yielded even more unambiguous results: Shock revival in 3D was either not achieved for progenitors that explode in 2D (Hanke et al. 2013; Tamborra et al. 2014b), or was delayed significantly (Takiwaki et al. 2014; Melson et al. 2015b; Lentz et al. 2015).”
A simple approach to the supernova progenitor–explosion connection (2016, background): “…successes in 3D explosion modelling (Melson, Janka & Marek 2015a ; Melson et al. 2015b; Lentz et al. 2015 ; M¨uller 2015), obtaining explosions has proved more difﬁcult in 3D multigroup neutrino transport models than in 2D (Hanke et al. 2013; Tamborra et al. 2014; Takiwaki, Kotake & Suwa 2014).”
THE ROLE OF TURBULENCE IN NEUTRINO-DRIVEN CORE-COLLAPSE SUPERNOVA EXPLOSIONS (2014, background): “The handful of 3D simulations including sophisticated neutrino transport have somewhat dashed those hopes, however, as they fail to explode, even for progenitors that explode in 2D (Hanke et al. 2013; Tamborra et al. 2014).”
Gravitational wave signals from 3D neutrino hydrodynamics simulations of core-collapse supernovae (2016, methodology): “2 (Tamborra et al. 2014b) is based on the solar-metallicity 11.2M (cid:2) progenitor of Woosley et al. (2002).”
NEUTRINO-DRIVEN EXPLOSION OF A 20 SOLAR-MASS STAR IN THREE DIMENSIONS ENABLED BY STRANGE-QUARK CONTRIBUTIONS TO NEUTRINO–NUCLEON SCATTERING (2015, background): “However, previous 3D simulations of this group for 11.2, 20, and 27 M progenitors had not produced explosions until ∼400–550 ms after bounce, although corresponding 2D models had exploded (Hanke et al. 2013; Tamborra et al. 2013, 2014a,b).”
Self-induced neutrino flavor conversion without flavor mixing (2016, background): “However, the recently discovered LESA phenomenon (lepton-emission self-sustained asymmetry) implies that the relative fluxes show a strong hemispheric asymmetry [38].”
A TWO-PARAMETER CRITERION FOR CLASSIFYING THE EXPLODABILITY OF MASSIVE STARS BY THE NEUTRINO-DRIVEN MECHANISM (2015, background): “…because current 3D simulations agree in showing slower explo- sions compared to 2D calculations or even no explosions (e.g., Hanke et al. 2012, 2013; Tamborra et al. 2014; Mezzacappa et al. 2015; Couch 2013; Couch & O’Connor 2014; Takiwaki et al. 2014) although some studies have proclaimed the…”
Evolutionary roads leading to low effective spins, high black hole masses, and O1/O2 rates for LIGO/Virgo binary black holes (2017, background): “Models without strong magnetic fields are unable to produce significant neutrino kicks (Tamborra et al. 2014).”
Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 1: The LBNF and DUNE Projects (2015, background): “Furthermore, neutrino emission from the supernova may exhibit an emitted lepton-flavor asymmetry [127], which would lead to observed rates being direction-dependent.”
NEUTRINO-DRIVEN SUPERNOVA OF A LOW-MASS IRON-CORE PROGENITOR BOOSTED BY THREE-DIMENSIONAL TURBULENT CONVECTION (2015, background): “…more massive progenitors 3D turbulence appears less supportive for the initiation of explosions than 2D flows (cf. references above and Hanke et al. 2013; Tamborra et al. 2014 for 11.2, 20, 27 M models), we investigate here whether 3D can strengthen the explosion after the onset of shock runaway.”
Non-Radial Instabilities and Progenitor Asphericities in Core-Collapse Supernovae (2014, background): “Among the available 3D neutrino hydrodynamics simulations, those (Hanke et al. 2013; Tamborra et al. 2014) relying on what is currently the most rigorous approach to neutrino transport and the most comprehensive treatment of the neutrino microphysics still fail to show explosions.”
The overarching framework of core-collapse supernova explosions as revealed by 3D fornax simulations (2019, methodology): “To summarize, the advantages of Fornax are: 1) it does not employ the simplifying “ray-by-ray” approximation used by many others (Tamborra et al. 2014; Lentz et al. 2015; Melson et al. 2015; Müller 2015; Takiwaki et al. 2016; Müller et al. 2017; Summa et al. 2018) that suppresses the important…”
THREE-DIMENSIONAL CORE-COLLAPSE SUPERNOVA SIMULATED USING A 15 M⊙ PROGENITOR (2015, background): “M (Tamborra et al. 2013, 2014; Hanke 2014) and 27-”