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Gravitational collapse of stellar cores and
Supernovae
(neutrino fluxes and shock waves)
D.K. Nadyozhin
Institute for Theoretical and Experimental Physics
ITEP, Moscow, Russia
23rd European Cosmic Ray Symposium
Moscow, Russia, July, 3 - 7, 2012
Core-collapse SNe (all other Types but Ia)
The SN outburst is triggered by the gravitational collapse of
the “iron” core of a mass MFe=(1.22) M into a neutron star.
About (1015)% MFec2 is radiated in the form of neutrinos
and antineutrinos of all the flavors (e, , ):
53
E = (3  5)  10 erg
The explosion energy (kinetic energy of the envelope expansion):
Eexp = (0.52)1051erg
it comes from the shock wave created at the boundary between
a new-born neutron star and the envelope to be expelled.
-3
Eexp /E
3  10
!!
Rich nucleosynthesis — from neutrino-induced creation of light element
in C-O and He shells through synthesis of heavy nuclides
by neutron capture at the bottom of expelled envelope
Neutrino from collapsing stellar cores
E = (3  5)  10 erg
53
Nonthermal
e
E tot  E
Thermal

The cumulative neutrino light curve
(based on Nadyozhin 1978)
Thermal component
from the neutrinosphere:
1
E e  E  E  3 E
( i   i  i , i  e,  ,  )
 e, e  10 MeV,
 ,   ,  25 MeV
Characteristic time
of the neutrino light curve tail  1020 s
Nonthermal component:
the sharp peak comes from
nonequilibrium
neutronization of stellar matter
Mostly electron neutrinos νe of individual energy:
• 15-20 MeV for spherically-symmetrical collapse
• 30-40 MeV for rotational-fission model is necessary
to interpret the statistically significant signal from
SN 1987A registered by the LSD neutrino detector
Characteristic duration of the peak < 0.5 s
About of 10% of total E is radiated in the peak
adapted from
A.G. Aksenov et al. Astronomy Letters 23, No. 6 (1997)
SN «visible» ejecta
1.2 ly
Circumstellar Ring
SN 1987A 16 years old (HST Nov. 28, 2003)
Interaction of shock wave with the circumstellar ring
January 2005
Chandra X-ray 0.4–0.7 keV
Observation Time 8 hours
HST Optical
B. Leibundgut 16th Workshop on Nuclear Astrophysics, Ringberg Castle,
Germany, March 26-30, 2012
http://www.mpa-garching.mpg.de/Hydro/NucAstro/prog12.html
Results of obsevations
Central dust cloud has a form of a prolate
ellipsoid with the axis ratio about 2.5.
The ellipsoid lays in the plane of equatorial ring
and expands with the velocity of ~3000 km/s.
The dust is heated by X-rays from the ring and
by the decay of Ti44 and radiates in far infrared.
44
Ti  Sc 
44
44
Ca ( =78.2 y)
Central stellar remnant is not yet seen being
screened by the dust.
Interaction of supernova ejecta
with circumstellar medium
R ~ t ,   0.50.9
Nadyozhin (1981, 1985), Chevalier (1982)
Conclusion
The neutrino detectors capable to separate the contributions
from different types of neutrino in the registered signal are
of great value for detection of neutrino signal from
gravitational collapses in our Galaxy.
Such detectors are those that contain scintillator+Fe,
for example, LSD (Mont Blanc) and LVD (Gran Sasso).
The rremnant of SN 1987A is a natural laboretory
for studying the origin of cosmic rays.
Close collaboration between supernova and cosmic ray
people is extremely welcome.