neutrinos in and from core-collapse supernova explosion · neutrinos in and from core-collapse...
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Neutrinos in and from Core-Collapse Supernova Explosion
Bernhard Müller(Monash University)
F. Hanke, L. Hüdepohl, H.-Th. Janka, A. Marek(Max-Planck-Institut für Astrophysik, Garching)
I. Tamborra (U Amsterdam), G. Raffelt (MPI for Physics)
Part I: Can we understand neutrino emission in supernova within an error margin of ~5%? Is it
necessary?
Structure of the Proto-Neutron Star and its Environment
“radiative equlibrium”
prot
o-ne
utro
n
star
cor
e
mantle
gain region
cooling region
PNS convection
radiation pressure (,e+,e-)
baryon-dominated, modified by interaction effects & electron
degeneracy
baryon pressure (ideal gas, non-degenerate)
nuclear forces dominate
EoS
CC (absorption)
CC & NC, modified by in-medium effects
CC & NC
CC & NC, modified by in-medium effects
Little interaction
Pair processes, NC, energy-exchanging
scatteringEnergy-exchanging
scattering, light cluster breakup
NC (in-medium), equilibrium diffusion
electron (anti-)neutrinos heavy flavor neutrinos
Do the opacities close to the neutrinosphere matter?
● During accretion phase: diffusive flux from PNS core + accretion luminosity (typically dominant, well under control?)
● Heating conditions (critical time-scale) ratio extremely sensitive to luminosities and mean energies: tadv/theat~(LE
2)5/3
● Required accuracy: <5%
● Ye during wind phase even more sensitive (to difference of electron neutrino and antineutrino luminosity and mean energy)
● Example: significant effect of electron neutrino-antineutrino annihilation into heavy flavor neutrinos on shock radius
Buras et al. (2003)
With neutrino-antineutrino annihilation source for /
With neutrino-antineutrino annihilation source for /
shock radius
● Inverse effect: neutrino-nucleon scattering of heavy flavour neutrinos deep in the cooling region
● Recoil energy transfer from /
to the medium
allows stronger (anti-)e emission in cooling
region → increase in heating in gain region
● Further rate uncertainties: break-up of light clusters, improvement of bremsstrahlung process?
Effects of Neutrino Treatment on the Heating Conditions
Fraction of binding energy pumped into accreted material before it leaves the gain region
Müller et al. (2012a)
The Role of Non-Isoenergetic Neutrino-Nucleon Scattering
“radiative equilibrium”
sets temperature
stratification
addit
ional
heat
ing
by /
com
pens
ator
y
cooli
ngprot
o-ne
utro
n
star
cooling region
gain region
density
cooling region
lum
inos
ity
radius
Neutrino opacities matter and may explain discrepant results of different modeling groups!
Müller et al. (2012a)
Cooling Phase: Rate Sensitivities
● Mean energies: ● Qualitatively similar rate
sensitivities as during pre-explosion phase
● ee↔XX and recoil energy
transfer in -nucleon scattering lower / energies
● Cooling time-scale● opacities above nuclear matter
densities become important
● Drastic reduction of cooling time-scale due to nucleon correlations (how uncertain?)
● Importance of interaction potentials (Martínez-Pinedo et al. 2012, Roberts el. al. 2012) → EoS plays a direct role
Hüdepohl et al. (2010): 8.8 M⊙ progenitor with
O-Ne-Mg core (explodes in 1D)
“Bruenn opacities”
“full” opacities (including nucleon correlation)
Is the PNS interior spherically symmetric?
● LESA: Global lepton flux asymmetry in recent 3D models of the MPA group (Tamborra et al. 2014)
● Accretion instability or low-mode nature of PNS convection responsible?
Tamborra et al. (2014)
Implications
● Seed for global asymmetry in convective models?
● Helpful for neutrino-driven explosions?
● Ratio of electron neutrino to electron antineutrino luminosity determines Ye in outflow
● Asymmetric Ye in wind phase?
● Stability analysis required to corroborate LESA as a physical effect.
proton-rich
neutron-richWanajo et al. (2011)
Transition to wind phase in electron-capture supernova
Part II: Probing the Supernova Core with Neutrinos
What will observations of a Galactic supernova tell us about the supernova engine?
Neutrino Signal – Overview● Electron neutrino burst
after bounce
● Accretion phase:
● Gray-body law for /:
● Additional accretion contribution
for e and e
● e mean energy~neutron
star mass
● Signs of the explosion?
onset of explosion
Lacc~GM M /R
L~4 R2T 4
27 M8 model, spherical integration of the total neutrino flux
Müller et al. (2014)
Can we learn more about the dynamics?
25 M8
● Exploit temporal variations of the signal as fingerprints of multi-D instabilities!
● Exemplary cases:● Supernova models as
seen by the IceCube detector at a distance of 10kpc
● No non-linear flavor conversion & ordinary mass hierarchy assumed
flux flux
Detecting Shock Oscillations
Non-exploding 25 M8 model
● Sloshing motions result in quasi-periodic and asymmetric neutrino emission
● Sloshing frequency related to shock and proto-neutron star radius
● Modulations survive in 3D (Tamborra et al. 2013)
● Detectable in IceCube for up to ~10 kpc
● Opportunity to reconstruct shock trajectory!
Müller et al. (2014)
period∝ rshock3/ 2 ln
r shockrPNS
● Sloshing motions result in quasi-periodic and asymmetric neutrino emission
● Sloshing frequency related to shock and proto-neutron star radius
● Modulations survive in 3D (Tamborra et al. 2013)
● Detectable in IceCube for up to ~10 kpc
● Opportunity to reconstruct shock trajectory!
Detecting Shock Oscillations
Müller et al. (2014)
Signatures of the Explosion
oscillatory “sloshing”
27 M8 explosion model
● Explosion phase characterized by slowly-changing large-scale anisotropies
● → emission modulation periods >20 Hz
● Weak explosions: possible emission spikes due to “early fallback”
Signatures of the Explosion
radial velocity
entropy
15 M8 explosion model
● Explosion phase characterized by slowly-changing large-scale anisotropies
● → emission modulation periods >25ms
Signatures of the Explosion
15 M8 explosion model
● Explosion phase characterized by slowly-changing large-scale anisotropies
● → emission modulation periods >25ms
Signatures of the Explosion
● Explosion phase characterized by slowly-changing large-scale anisotropies
● → emission modulation periods >25ms
● Weak explosions: possible emission spikes due to “early fallback”
11.2M8 explosion model
Müller et al. (2014)
Signatures of the Explosion
● Explosion phase characterized by slowly-changing large-scale anisotropies
● → emission modulation periods >25ms
● Weak explosions: possible emission spikes due to “early fallback”
Müller et al. (2014)
Summary
● Accuracy on the percent level required to model the effect of neutrinos in supernovae correctly (heating, Ye in outflow)
● Some opacities may need to be revisited to achieve this goal:● heavy flavor neutrino reactions at neutrinospheric densities
(bremsstrahlung, light cluster breakup)
● PNS cooling: Nucleon interaction potentials and correlation effects at high densities (neutrino observations may help)
● Global lepton flux asymmetries need to be understood
● Time-frequency structure of the neutrino signal as a more powerful probe of supernova dynamics