Gravitational collapse of stellar cores and Supernovae

(neutrino fluxes and shock waves)

23rd European Cosmic Ray SymposiumMoscow, Russia, July, 3 - 7, 2012

D.K. Nadyozhin

Institute for Theoretical and Experimental PhysicsITEP, Moscow, Russia

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=(1.22) M into a neutron star.

About (1015)% MFec2 is radiated in the form of neutrinos and antineutrinos of all the flavors (e, , ):

The explosion energy (kinetic energy of the envelope expansion):

Eexp = (0.52)1051erg

it comes from the shock wave created at the boundary between a new-born neutron star and the envelope to be expelled.

erg= ( ) 53E 3 5 10

exp3-E 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 coresNeutrino from collapsing stellar coreserg= ( ) 53E 3 5 10

The cumulative neutrino light curveThe cumulative neutrino light curve(based on Nadyozhin 1978)

Nonthermale

Thermal

totE E

Characteristic time of the neutrino light curve tail 1020 s

1e 3

e, e

, ,

Thermal component from the neutrinosphere:

( , e, , )

10 MeV,

25 MeV

E E E

i ii i

E

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 sAbout of 10% of total is radiated in the peakE

A.G. Aksenov et al. Astronomy Letters 23, No. 6 (1997)adapted from

SN 1987A 16 years old SN 1987A 16 years old (HST Nov. 28, 2003)(HST Nov. 28, 2003) Interaction of shock wave with the circumstellar ringInteraction of shock wave with the circumstellar ring

Circumstellar Ring

SN «visible» ejecta

1.2 ly

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.

Central stellar remnant is not yet seen being screened by the dust.

444 4 44 CaTi Sc ( = 78.2 y)

Nadyozhin (1981, 1985), Chevalier (1982)

Interaction of supernova ejecta Interaction of supernova ejecta with circumstellar mediumwith circumstellar medium

R ~ t , 0.50.9

ConclusionThe 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 laboretoryfor studying the origin of cosmic rays.

Close collaboration between supernova and cosmic ray people is extremely welcome.