Neutrino Burst from Supernovae and Neutrino Oscillation

Katsuhiko Sato (Univ.Tokyo)Katsuhiko Sato (Univ.Tokyo)Collaborators: Collaborators: K. Takahashi, S.Ando, T. Totani, K. Kotake, S. Yamada,K. Takahashi, S.Ando, T. Totani, K. Kotake, S. Yamada,T. Shimizu, S. EbisuzakiT. Shimizu, S. Ebisuzaki

J. Wilson,J. Wilson, S. Dalhed, A. Burrows and T. Thompson S. Dalhed, A. Burrows and T. Thompson

-What is the effect of neutrino OSC on explosion and the detection? -Can we extract OSC parameters from the neutrino observations ?

Plan of this talk

IntroductionIntroduction A brief review of gravitational collapse-driven A brief review of gravitational collapse-driven

supernovasupernova Neutrino OSC in supernova and the detectionNeutrino OSC in supernova and the detection

-Constraint on OSC parameters from the detection of -Constraint on OSC parameters from the detection of supernova neutrino burst – supernova neutrino burst –

Effects of rotation on explosion and neutrino burst Effects of rotation on explosion and neutrino burst （（ Gravitational wave from supernovaeGravitational wave from supernovae ））

Supernova １９８７ A in LMC ２３ Feb. ７：３５ AM （ UT ），１９８７

10 10 trillion neutrinos trillion neutrinos passed through your passed through your body.body.

Huge water Cerenkov Huge water Cerenkov counters could detect counters could detect this neutrino burst, this neutrino burst,

11 events11 events by by Kamiokande & Kamiokande &

8 events8 events by IMB . by IMB .

Direct evidence that SN is triggered by gravitational collapse of stellar cores. Remarkable achievement which remains in history.

Nobel Prize was awarded to Dr. M. Koshiba, the head of Kamiokande, Professor emeritus of the Univ. of Tokyo.

FromFrom 　　 http://www.nobel.se/http://www.nobel.se/

We have been waiting the prize more than 15 years　！

Now huge neutrino detectors are running! If a supernova appears at the Galactic center, then almost If a supernova appears at the Galactic center, then almost 10,000 events10,000 events at SK at SK 　 　 　　 　 　 and and 　 　　　　　　　　　 　　　　　　　　 350 events350 events at SNO are expected. at SNO are expected.

Total mass:10,000t, Fiducial mass:3,200t 　 30xKamII

1,000tD2O, 1.400t H2O

Now we must consider seriously what astrophysics/physics are obtained from the detection of supernova neutrino burst.

800 events

At LVD.

56Fe+e->56Mn+νe

If　M　>　8-10　Msolar,　　Iron　core　is　formed.

–10 9.5g/cm　3 Unstable　and　begins　to　collapse.Neutrinos　can　escape　from　the　core　without　scattering.

–10 11g/cm　3 　 The　mean　free　path　becomes　shorter 　 than　　　　　　　　　　　　　　　　　　　　the　core　radius,　core,　lmfp<R.

–10 12g/cm　3 The　diffusion　time　τdif= mfpcR

2

becomes　longer　than　the　characteristic　collapsing　time　scale　τff　.. 　 　 τdif

>τff ..

νν

lmfp

Neutrinos　are　trapped,　and　are　degenerate　Neutrinos　are　trapped,　and　are　degenerate　in　SN　cores.in　SN　cores.

Collapse of Stellar Cores and Neutrino TrappingCollapse of Stellar Cores and Neutrino Trapping(K. Sato’75)(K. Sato’75)

Neutrino reactions in supernova cores

emission, absorption,scattering on nucleons

scattering on electrons

emission, absorption,scattering on nuclei

-pair creations,annihilations

Neutrinos are trapped by the effect of coherent scattering (Sato,’75) since the cross section proportional to A2 ,and is larger.

How nuclei melt into supernova matter / neutron star matter ?

Just after the glitches of pulsars were discovered.

Coherent scattering depends on the size and shape of nuclei .

How nuclei melt in the course of collapse? Important for opacity

“Nuclear Pasta “ Structure With increasing matter density, the shape With increasing matter density, the shape changes from sphere,cylinder,slab, changes from sphere,cylinder,slab, cylindrical bubble,spherical bubble and cylindrical bubble,spherical bubble and eventually becomes homogeneous.eventually becomes homogeneous.

(Ravenhall & Pethick.,83, Hashimoto et al,84, (Ravenhall & Pethick.,83, Hashimoto et al,84, Oyamatsu et al., 84,…Maruyama et al., 98, Watanabe Oyamatsu et al., 84,…Maruyama et al., 98, Watanabe

et al., 00, and 01, Iida et al.,01)et al., 00, and 01, Iida et al.,01)

Essentially this change is described by the surface Essentially this change is described by the surface energy energy

minimum principle.minimum principle.

3/2)(

_

volume

areasurfaceg

Oyamatsu,93

How the structure changes with increasing temperature?

Perturbation analysis with the analogy of liquid crystal Pethick, Pethick, Potekhin,98, Watanabe et al., 00Potekhin,98, Watanabe et al., 00

QMD method is suitable for investigating the melting by finite temperature (Maruyama et al. 98).

Recently we improved this method and succeeded to construct pasta structure (Watanabe et. al .,01,02,03).

From Oyamatsu et al., 84From Oyamatsu et al., 84

Model:Model:

N= 2048N= 2048

T~0.1MeVT~0.1MeV

X=p/(p+n)=0.3X=p/(p+n)=0.3

Results of QMD calculation (Watanabe,Sato,Yasuoka,Ebisusaki; PRC ’02)

Sphere(0.1ρ ０）

slab (0.35ρ ０）

cylinder (0.18ρ ０）

Cylinder hole (0. ５ ρ０）

Spherical hole (0.55ρ０）

Preliminary result on the melting with increasing temperature: Model:N= 2048,ρ~0. ３５ ρ ０ , X=p/(p+n)=0.5

T=1MeV T=2MeV (slab)

T=3MeV

T=0.1MeV (cylinder+slab)

T=5MeVT=4MeV (almost homogeneous)

Two-point correlation function ξ of the nucleon density fluctuations δ

with &

uniform　phaseat　T>4-5MeV

ξ(r)=0　at　larger　r

disappearance　of　long-range　correlation

at　T=5MeV

Nucleon Distributions for X=p/(p+n)=0.3 and ρ=0.175ρ0

Cylinder　phase　at　T=0ρ=0.175ρ0

N=2048,　Np=614,　Nn=1434box　size=41.394fm

T=1MeV T=2MeV T=3MeV

T=4MeV

T=3,　4MeV　:　　Nuclear　surface　cannot　be　identified　by　an　isodensity　surface.

Nucleon Distributions for x=0.3 and ρ=0.35ρ0

Slab　phase　at　T=0ρ=0.35ρ0

N=2048,　Np=614,　Nn=1434box　size=32.85fm

T=0MeV T=1MeV T=2MeV

T=3MeV

T=3MeV　:　　Nuclear　surface　cannot　be　identified　by　an　

isodensity　surface.

Phase Diagrams for ｘ＝０．３　χ　>　0‹H›　>　0

　χ　=　0‹H›　>　0

　χ　<　0‹H›　>　0

　χ　=　0‹H›　=　0

　χ　<　0‹H›　<　0

　χ　=　0‹H›　<　0

　χ　>　0‹H›　<　0

ｘ＝ 0.3

phase-separating　region

limit　for　identification　

of　nuclear　surface

Structure　with　χ<0　(“intermediate”　phase)　:　　Sponge-like

χ　=　(number　of　isolated　regions)　–　(number　of　

tunnels)+　(number　of　cavities)

Euler characteristic

Still preliminary, but systematic investigation is in progress.

Eventually　the　shock　revived　by　　ν 　 deposition,　and　outer　shells　are　expelled.　Delayed　Explosion(Wilson)

Eventually　the　shock　revived　by　　ν 　 deposition,　and　outer　shells　are　expelled.　Delayed　Explosion(Wilson)

-10 15g/cm　3

Inner　core

shockThe　core　bounces　and　theunshocked　inner　core　is　formed.The　shock　isgenerated　at　the　surface.Unshocked　core　playasa　role　of　spring　for　explosion.

If　the　shock　is　sufficiently　strong,　the　star　explodes;　Prompt　explosion　However,　most　simulations　show　it　is　insufficient　for　explosion,　andstalled　.　　　No　prompt　explosion　occurs　in　realistic　sim.

If　the　shock　is　sufficiently　strong,　the　star　explodes;　Prompt　explosion　However,　most　simulations　show　it　is　insufficient　for　explosion,　andstalled　.　　　No　prompt　explosion　occurs　in　realistic　sim.

•νInner　coreν

ν

ν

ν

νν

νν

An example of delayed explosion late time explosion by ν-heating

shock

The stalled shock is revived by the neutrino deposition from the proto-neutron star. Wilson ‘82

The latest example of LLL group: the general relativistic core-collapse simulation with full νtransport calculation (Totani, Sato, Dalhed, Wilson,’98)

Pre-supernova Model:Weaver & Woosley 20 Solar Mass.

108109

Neutrino Burst from SN

1.The latest neutrino burst models of the LLL group (pre-SN model:Weaver, Woosely 20 Msolar ) (Totani,Sato,Dalhed, Wilson,’98).

Time evolution of ν luminosity & the average energies

npe e

<E>=10MeV

<E>=15MeV

<E>=23MeV

(νμ 、 ντ and their antiparticles)

Latest simulations with updated neutrino processes and sophisticated neutrino transfer show no explosion.

Liebendoerfer et al. ‘01

Rampp et al. ’00,’03 Thomson et al. ‘02

1. Microphysics (neutrino processes, EOS etc.) are still insufficient ?

Something important processes are missed?

2. Computational methods ( neutrino transfer , convection, etc) are still unreliable?

3. Spherical symmetric simulation is inadequate. Stellar rotation and/or magnetic field play essential role for explosion ?

Why no explosion?

In the present neutrino OSC analysis of supernova neutrino burst,

We employ two models

1. LLL models (Totani et al, ’98) as the full neutrino burst model (~ 15 sec). (only one full time neutrino burst model available today)

2. Burrows’s group model (Thomson et al, ’02) as an early phase burst model (~ 0.2 sec.). (as a representative of latest simulations)

2.TBP (Thompson,Burrows,Pint) Model (early 0.2 sec burst)Evolution of luminosity

Evolution of average energies

<E>=12MeV <E>=15MeV <E>=20MeV

The early phase analysis has advantage in that it is not affected whether the remnant is a neutron star or a black hole.

(Takahashi, Sato, Burrows, Thompson, PRD‘03)

Neutrino OSC and Neutrino Burst from Supernovae

1. What is the effect on Explosion ?

If we take values of oscillation parameters suggested by solar ν and atmospheric ν obs., no resonances occur in the core, but they occur in the mantle of SN (C+O shell, He shell) .

No effect on explosion.

Note: If Δm ~101-2ev, resonance happens in the hot bubble region, energy deposition is greatly enhanced because of the large cross section of high energy electron type neutrinos. Explosion is greatly strengthened (Shramm et al , …..)

SK and SNO showed clearly neutrinos have masses, and oscillate.

13

2.What are the effects on the detection?

In order to get original information of cores and to extract the explosion mechanism, it is essentially important to know how the spectra of the neutrino burst are modified by neutrino OSC.

3. Can we extract osc parameters from the neutrino observation if a Galactic supernova appears ?

Supernova is the strongest source of three type of neutrinos in the universe. (Sun e- type only, atmospheric neutrinos e- and μ- type)

i) Can we obtain the implication on the parameter ,which has not yet determined?

ii) Can we solve the mass hierarchy problem ?

Inverted mass hierarchy model (m(mνμ>m>mνe>>m>>mντ)) has not yet ruled out by experiments.

Resonance in Supernova Mantle –normal hierarchy model-

Resonance Condition:Resonance Condition:

H He C,O

Ne,Mg

Si Fe

EG

mnn

F

rese22

2cos2

Dighe,Smirnov, ’00

Lunardini,A.Y.Smirnov,01

Minakata, Nunokawa.’01

Takahashi,Sato, ’01

Takahashi et al,’01

………….

Neutrino OSC Models

LMA-LLMA-L 0.870.87 1.01.0 0.0430.043

LMA-SLMA-S 0.870.87 1.01.0

SMA-LSMA-L 1.01.0 0.0430.043

SMA-SSMA-S 1.01.0

232 2sin 13

2 2sin 213m

3100.5 3100.5

6100.1

6100.1

5100.7 5100.7 6100.6 6100.6

3102.3 3102.3 3102.3 3102.3

122 2sin 2

12m

710212

m　　　　　　　　： from solar neutrinos, : upper limit from nuclear

: atmospheric neutrinos 　 　 　 　 　 　 　 　 　 　 　 　 　 reactor

12

23

212m

213m

Inverted mass hierarchy models are denoted as

Inv-LMA-L, Inv-LMA-S, Inv-SMA-L, Inv-SMA-S.

13

Time evolution of conversion probability for LMA-L and LMA-S

νe νe

ντντ

νe

ντ

Event rate at SK for LLL neutrino burst ModelWe calculate the event rate and the energy spectra at SK, assumingSN appeared at GC(10kpc).

nepe

_

ee ee

_ ee ee

ee xx _

ee xx

NeOe

_

FeOe

Most of events come from nepe

_

Time evolution of event rate expected at SK

Time-integrated Energy spectra and Event numbers

Can be distinguished from the ratio of event rate at the peak region to the tail region.

Most of events come from .

effect of vacuum OSC. 　 　 νe 　 　νμ 、 τ

Models with larger mixing angle deviate from no osc model.

nepe

_

Event rate at SNO for LLL neutrino burst Model

1,000t 　 D2O, 　 （ 1.400t H2O ）

Important reactions

Electron type neutrinos can be detected efficiently by

)(CCppede

)(_

CCnnede )(NCpnd xx

ee xx

We discuss only CC, not NC.

Time evolution of event rate expected SNO

Energy spectra and Event numbers

Events come from the both .

both effects, vacuum OSC and MSW.

with increasing mixing angle, event number increases.

ee ,_

Can be distinguished from the ratio of event rate at 15Mev region to the E>30Mev region.

Case of Normal mass hierarchy Case of Normal mass hierarchy 　　　　　　　　　　　 　　　　　　　　　　　 Case of inverted mass hierarchy Case of inverted mass hierarchy 　　　　　　 　　　　 　　　　　　 　　　　 Crossing diagram for antineutrinos

)( 31 mm

m1

m2

m3

e

)( 31 mm

No Level crossing No Level crossing

3

2

1

e

H-resonanceH-resonance

H-resonance happens H-resonance happens for anti neutrinosfor anti neutrinos

If the resonance is If the resonance is adiabatic (large adiabatic (large 　　 　　 ),), conversion conversion occurs effectively.occurs effectively.

13 ,e

ne

Case for inverted mass hierarchy

Event rate is greatly increased !

The time-integrated energy spectra

　　 ννee events are increased events are increased by by H-resonance: ντ 　 νe.

13,084 events

10,245events

68

185

237

82

190

118

111

In order to extract information of mixing angle, we define the ratios, R(SK) and R(SNO),

R(SK) and R(SNO) are good indicators for neutrino OSC.

)20~5(

)70~30()(

MeVEvents

MeVEventsSKR

)20~5(

)70~25()(

MeVEvents

MeVEventsSNOR

Plots on RSK-RSNO plane (Error –bars represent only statistical errors.)

nor-LMA-s and inv-LMA-s are degenerate, but inv-LMA-L is clearly nor-LMA-s and inv-LMA-s are degenerate, but inv-LMA-L is clearly discriminated from nor-LMA-L. If the mixing parameter discriminated from nor-LMA-L. If the mixing parameter 　　　　　　 is -L, is -L, mass hierarchy problem is solved.mass hierarchy problem is solved.

)(CCppede

Anti neutrino events can be subtracted by neutron detection.

13

Analysis by using the TBP burst model

This simulation was done by using the updated This simulation was done by using the updated neutrino processes and sophisticate neutrino neutrino processes and sophisticate neutrino transfer program.transfer program.

Available data are only the initial 0.2 second of the Available data are only the initial 0.2 second of the neutrino burst, but this early phase analysis has neutrino burst, but this early phase analysis has advantage that it is not affected whether the remnant advantage that it is not affected whether the remnant is a neutron star or a black hole.is a neutron star or a black hole.

We investigated the dependence on the pre-supernova We investigated the dependence on the pre-supernova mass. We found the results are almost independent mass. We found the results are almost independent of the masses. of the masses.

Evolution of the burst and time-integrated energy spectra (TBP model)

Presupernova-mass dependence on R(SK)-R (SNO) Plots

nor-LMA-s and inv-LMA-s are degenerate, but inv-LMA-L is clearly nor-LMA-s and inv-LMA-s are degenerate, but inv-LMA-L is clearly discriminated from nor-LMA-L. If the mixing parameter discriminated from nor-LMA-L. If the mixing parameter 　　　　　　 is -L, is -L, mass hierarchy problem is solved.mass hierarchy problem is solved.

Error bars come from only statistical errors, which are increased because the event numbers becomes small.

)20(

)20()(

MeVEEvents

EMeVEventsSNOR

)20(

)20()(

MeVEEvents

EMeVEventsSKR

13

The Earth effects on the supernova neutrinosSupernova neutrinos oscillate and are reconverted Supernova neutrinos oscillate and are reconverted each other in the earth.each other in the earth. 　　 The spectra are greatly The spectra are greatly modified if they pass through the earth.modified if they pass through the earth.

Pass length when SN occurs at Galactic center.

t=0 : the time at which the SN is aligned with the Greenwich meridian.

(Dighe &Smirnov (00,01), Takahashi & Sato (00, 01) )

Earth

SK 9500 events

SNO300 events

LVD850 events

In order to analyze the earth effect and to get information on OSC parameters, we need to know supernova direction, which is determined accurately by electron scattering.

Electron scattering Electron scattering has sharp forward has sharp forward peak, but the fraction peak, but the fraction of is ~ 3% (282 of is ~ 3% (282 events/total 8441 for events/total 8441 for Galactic Center Galactic Center Supernova at SK)Supernova at SK)

Monte Carlo Simulation of recoiled e- (e+) direction for SK: Most of the events are by nepe

_

By using the least-square method, we get the direction within the accuracy 7degree (1σ ）。Ando & Sato, ‘01

Modification of the spectraSpectra are greatly modified by MSW effects in the earth.Spectra are greatly modified by MSW effects in the earth.

Case: Case: LMA-SLMA-S,, 　　 nadir angle =0nadir angle =0 (pass through the center) (pass through the center)

The spectra depend sensitively on the nadir angle

and Since the nadir angle can be determined from the scattering by electrons at Since the nadir angle can be determined from the scattering by electrons at SK or SNO, could be determined more precisely by the earth SK or SNO, could be determined more precisely by the earth effects.effects.

212m

212m

nadir angle dependence 　 　 　 　 　dependence

212m

Supernova Relic NeutrinosSupernova Relic Neutrinos and its detectability

There should be a diffuse background of There should be a diffuse background of neutrinos emitted from past supernovae. neutrinos emitted from past supernovae. (Supernova Relic Neutrino Background, or (Supernova Relic Neutrino Background, or SRNSRN))

Ando, Sato, Totani ’02, Ando , Sato ‘03

Flux depends on the history of supernova rate and neutrino oscillation parameters.

We investigated the dependence of the flux on the OSC parameters, and effects on the detectability.

Flux is increased greatly if LMA, and if inverted mass hierachy.

Cosmic timeWe are here.

z=0

z=1

z=5

History of Supernova Rate The SN rate model is evaluated from The SN rate model is evaluated from

corresponding SFR model based on corresponding SFR model based on optical/UV observation by HST.optical/UV observation by HST.

Particularly, behavior at high redshift is Particularly, behavior at high redshift is not known well. (Luminosity function is not known well. (Luminosity function is not established and dust extinction is not established and dust extinction is unknown.)unknown.)

However, owing to energy redshift, However, owing to energy redshift, neutrinos emitted at high-neutrinos emitted at high-z z contribute contribute only to low energy regiononly to low energy region (, where SK (, where SK does not have sensitivity)does not have sensitivity)..

Madau et al. (1996)Madau et al. (1996)

7.0,7.0,3.0 hm

The uncertainty around here is not The uncertainty around here is not important so much.important so much.

Flux for Various OSC Models We obtain the hardest We obtain the hardest

spectrum for the INV-L spectrum for the INV-L model.model.

The spectra for the other The spectra for the other LMA models are LMA models are degenerated. degenerated.

We also set upper limit for We also set upper limit for these oscillation models, by these oscillation models, by analyzing the spectrum with analyzing the spectrum with the SK observational result.the SK observational result.

Theoretical prediction and Observational Limit (SK)

modelmodelPredicted flux Predicted flux (cm(cmss))

SK limit SK limit (90%C.L.)(90%C.L.)

Prediction/ Prediction/ LimitLimit

NOR-SNOR-S 1212 < 35< 35 0.340.34

NOR-LNOR-L 1111 < 34< 34 0.330.33

INV-SINV-S 1111 < 34< 34 0.330.33

INV-LINV-L 9.09.0 < 12< 12 0.740.74

No oscillationNo oscillation 1212 < 73< 73 0.170.17

The upper limit is more severe for the INV-L model. The upper limit is more severe for the INV-L model. (In spite of difficult observation, SK upper limit is approaching the theoretical (In spite of difficult observation, SK upper limit is approaching the theoretical prediction. It is expected constraints on OSC parameters could be obtained near prediction. It is expected constraints on OSC parameters could be obtained near future.)future.)

Malek et al,’03Malek et al,’03

Effects of Rotation on the Supernova Explosion Massive stars have large angular Massive stars have large angular

momentum:momentum: q= J/(GMq= J/(GM22/C) ~ 10/C) ~ 10

Implications of rotational collapse Implications of rotational collapse and Jet-like explosion from and Jet-like explosion from SN1987A observations.SN1987A observations.

1.Observation of asymmetry of 1.Observation of asymmetry of expanding envelope by SPECKLE expanding envelope by SPECKLE (Papalios, et. al. 89)(Papalios, et. al. 89)

2.Observation of linear polarization of 2.Observation of linear polarization of scattered photons (Cropper et al.88)scattered photons (Cropper et al.88)

3. Rings suggest pre-supernova was 3. Rings suggest pre-supernova was rapidly rotating.rapidly rotating.

Many groups have been challenging the simulation of rotational collapse of stellar cores.

Mesh code

2dim.

LeBranc, Wilson

Symbalisty

Moenchmeier et al (91)

Yamada, Sato

Shimizu, Yamada, Sato(94,01)

…..

3-dim.

Shimizu, Yamada, Sato (94)

SPH (Smoothed Particle Hydrodynamics)

Herant et al (’94)

Fryer (’99), Fryer et al (’01)

…………

Difficulties in simulation

multi-dimension neutrino transport

general relativistic treatment

………

All simulations are still preliminary ones.

Asymmetric -heating due to rotation

•If oblate proto neutron stars are formed due to centrifugal forces, more neutrinos are emitted in the direction of rotation axis.• Assuming an oblate proto neutron star is formed, we carried outhydrodynamic simulation, and found that -heating is enhanced near the rotation axis, and global convections are induced in heating regions.•As the result, Jet like explosion is induced.

Shimizu, Ebisuzaki, Sato, Yamada ,’01

oblate proto neutron star

2D Rotational Collapse SimulationsKotake, Yamada, Sato , ApJ595, 304 (03)

t = 256ms

Rad

ius

[cm

]

T [

MeV

]

0° 90°

Density

entropy

Shape of neutrino sphere becomes spheroid.

Temperature on the sphere

Neutrino luminosity and the average energy depend on what direction we observe.

We are investigating whether implication on OSC parameter could be obtained or not.

３

５

Gravitational Radiation from Axisymmetric Rotational Core Collapse

Preceding works and recent works

…… Moenchmeyer et al . ’91 Yamada, Sato, ’97 Zwerger & Mueller ’97 Dimmelmeier et al. ’02 Shibata ’03 Kotake,Yamada, Sato ’03 Ott et al., ’03

Kotake, Yamada, Sato, PRD68, 044023 (03)

We calculated gravitational radiation by using quadrupole radiation formula.

Most preceding works took simplified EOS, i.e. , p=Kργ , and neutrino emission/ absorption/transport are neglected.

We carried out collapse simulation by using realistic EOS (Relativistic MFA; Shen et al. ‘98 ) and included neutrino processes.

Theoretical prediction of “hTT” when SN appear at Galactic center and detection limit

We carried out for various rotation models, and found most of them are higher than TAMA detection limit.

Case of Moderate rotation

Example of wave pattern

Wave patterns depend on rotational speed and distribution of angular momentum.

Case of strong differential rotation

Small fluctuations disappear because of centrifugal force in the central core region.

If the gravitational wave is detected and wave pattern is observed, information on the rotation would be obtained.

Summary● Now huge neutrino detectors (SK, SNO,LVD,..) and supersensitive GW detectors (TAMA,LIGO,..) are working. 1.1.If SN appears at Galactic center, 10,000 events (SK) , and 350 events (SNO) will be detected, and fruitful information on the explosion mechanism and neutrino OSC parameters would be obtained. More huge detector Hyper Kamiokande is proposed. 2.TAMA and LIGO would detect gravitational waves from Galactic supernovae if precise time of explosion is informed by SK, and implication on the rotational speed and the stiffness of EOS could be obtained.

Despite almost 40 years of intensive and extensive studies, we still do not figure out how the collapse-driven supernova occurs 。

More extensive and systematic studies on gravitational collapse including realistic EOS and neutrino transfer are necessary.