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Hypernovae and Black HolesHypernovae and Black Holes野本憲一 (Nomoto, Ken’ichi)前田啓一 (Maeda, Keiichi)

東京大学大学院理学系研究科天文学専攻University of Tokyo, School of Science, De

partment of Astronomy

SN 1998bw

=

SN 1987A

E ~ 30×1051ergs E ~ 1×1051ergs

SNe Ic SNe IInSN GRB SN GRB

1998bw 980425 1997cy 9705141997ef 971115 1999E 9809101999as 1988Z2002ap 1999eb 9910021997dq1998ey1992ar

Hypernova CandidatesEkinetic > (5-10)×1051ergs SN 1998bw

GRB 980425

• Observations: Spectra, Light Curves– Progenitors, Energetic, M(56Ni)

• The properties of Hypernova Explosions– Features unexpected by spherical models– Black Hole Formation

• Jet-Driven Explosion Model– Explains the above features?– Predictions

• Evolution of the central black hole. • Nucleosynthetic features (e.g., 56Ni)• Gravitational wave (?) - Optical Display - Abundances

Possible Gravitational Wave from Hypernovae?

• MBH ~4M

• Low Viscosity Case M (R<300km)– 0.0033 M

• High Viscosity Case – 2.21 M– j~1017 cm2s-1

• Self-Gravity• Large EROT/|EGRAV|

Macfadyen et al. 1998

Bar Mode Instability?

R ~100km at Bounce

M~1M

J Conserve

j~1016cm2s-1

R ~100kmMDISK~2M

J Conserve

j~1017cm2s-1

h~4×10-20 (1Mpc/D) (j/1017cm2s-1) (M/M) (f/1000Hz)

f~1000 (j/1017cm2s-1) (100km/R)2 e.g., Fryer et al.2002

SN at 10Mpc (1SN/year); f~100 Hz, h~4×10-

23

HN at 100Mpc (1HN/year); f~1000 Hz, h~8×10-22

Ia

Ic

Ib

94I

97ef98bw

HeCaO

SiII

Hyper　 -novae

Spectra of Supernovae & Hypernovae

Hypernovae ：　　 broad features　　　　 blended lines 　　“ Large mass at hi

gh velocities”

Ic: no H,

no strong He,

no strong Si

Light Curves of Supernovae & Hypernovae

Light Curve Broadness

SN1998bw >> SN1994I

Ejected Mass

SN1998bw >> SN1994I

Progenitor’s Mass

SN1998bw >> SN1994I

Parameters [Mej, E, M(56Ni)]

Si

C+O

HeH-rich

MC+O

Fe Collapse56Ni

56Co

５６Fe

Mms/M MC+O/M

~ 40 13.8~ 35 11.0~ 22 5.0

Light Curve Spectra

~ [dyn • diffusion]1/2

~ • RV R c

Mej 1/2

½Mej¾E -¼

E Mej3

E Mej

CO Star Models for SNeIc 　　

５６ Ni

Spectral Fitting: SN1997ef

Model

Normal SN

Small Mej

Too Narrow Features

Spectral Fitting: SN1997ef

Model

Hypernova

Large Mej

Broad Features

Progenitors’ Mass – E – M(56Ni)

Most Stars (>25M) explode as Hypernovae?

• The Contribution of Hypernovae is Large.– Hypernovae are Not so Rare Events.

Distribution of HNe

Distance – Absolute Magnitude of SNe Ib/c

10 100 Mpc

• 1 HN per 1 year in R<100Mpc.

• 1 SN per 1 year in R<10Mpc.

Hypernova Rate

• Large Fraction of Massive O (or He) Star with M>20M Explodes as Hypernovae. Depending on Binary Evolution?

Local SN Rate (SN/100yr/1010L) h=H0/100

Ia Ib/c II All0.36±.11h2 0.14±.07h2 0.71±.34h2 1.21±.36h2

Corrected1)

Observed2) 111 18 54 1831)Cappellaro et al. 99, 2)Richardson et al. 01

HNIb/c

SNIb/c= 3(+1+2)/18

~ 0.15 – 0.3

N(20M-50M)

N(8M-20M)~ 0.3 (Salpeter IMF)

Properties of Hypernova Explosions

(1) Deviation from spherical explosion models(2) Black hole formation

1) Asphericity in Core-collapse SNe (in general)

HST Image of SN1987A

Wang et al. 2002Optical Spectropolarimetry of

SNe 1993J, 1996cb, Wang et al. 1999

SN1987A: Asymmetrical, but not spherical, ejecta

Optical Polarization in core-collapse SNe > 0.5 %(in SNe Ia < 0.2 - 0.3%)

1998bw

1997ef

2002ap

1998bw

1997ef

2002ap

High Density

Spherical Hydro Model

Low Density

(Vacuum)

2) Light Curves of Hypernovae

Maeda et al. 2003, ApJ, submitted

ObserverExpansion

Fe

O

Spherical

FeII] 5200A

[OI] 6300A

Observation

FWHM

3) Late time spectra of SN1998bwLine Width Inversion between Fe and O

Broader Fe lines than O lines in the observations.

Low velocity O-rich Matter: SNe1998bw, 1997ef

56Fe

16O

Spherical

Aspherical

15 deg

FeII] 5200A

[OI] 6300A

Maeda et al. 2002

Observation

Interpretation as an Aspherical explosion

• Enhancement of O,Mg,Si,S,Ti by a factor of 6-10. Israelian et al. 1999

Abundances in Nova Sco

-0.5

0

0.5

1

1.5

N O Mg Si S Ti Fe

[X/H

]

SN matter

BH

[X/H]=log10(X/H)-log10(X/H)

4) BH Formation

Hypernova model for the formation of the BH in Nova Sco

Abundance in Nova Sco

00.20.40.60.8

1

He C O Ne Mg Si S Ca Ti Fe

[X/H

]

E51=30BH mass in the model

4.8M at the explosion

5.4M now (Post SN)

SN

BH

MMS=40M, MHe=16M, E51=30

MBH at the explosion ~ 5M

Black hole formation with a Hypernova explosion.Podsiadlowski et al. 2002

The properties of hypernova explosions

• High velocity material (Fe)• Low velocity & high density material (O)

– Contrary to conventional spherical models. • forms a black hole, but explodes with large

E51 (= E/1051ergs > 10).– Black hole formation does not always leads to

a failed supernova.

Do jet-induced explosions satisfy these conditions?

16MHe (MMS=40), 8M

He (MMS=25), (Nomoto&Hashimoto 1988)

MRem0 1.0 – 3.0M

Ejet = Mc2 , 0.01

Model: Jet-induced Explosion

Newtonian　 Gravity

Radiation＋ Pairs 15o

Postprocessing

222 isotopes (Tielemann et al.)K. Maeda, in preparation

Hydrodynamics

Collimated jets (Z) + Bow shock (All direction)

M Lateral expansion

Radial Velocity/cLog (Density[g cm-3])

R/1010cm

Hydrodynamics (Center)

Accretion from the side

Continue to accrete, MBH

Radial VelocityDensity

R/1010cm

0.7 s

1.5 s

E51=11, MBH(final)=5.9M, M(56Ni)=0.11MOutflow

Inflow

R/1010cm

Density Distribution

Jet (z) (E51=11)

Jet (R)

Sph (E51=10)

Sph (E51=1)

High density core at the central region

High velocity material along z

Growth of a central remnant

Time (sec)

MBH

20 400

4

8 Inefficient Jet

efficient Jet

MREM can be ~ 5 – 10M, starting from 1.5 – 3M.

Still a strong explosion follows (E51>10).

A hypernova with a stellar mass black hole (X-ray Novasco; Large Si,S with black hole formation).

Final Remnants’ masses and Kinetic Energies

• A more massive star makes a more energetic explosion 　　　　　　　 (As seen in ‘Hypernova Branch’).

11 6.9

1.95.9

E51=E/1051ergs MBH(M)

Peak Temperature & Density

• High T + Low Material are preferentially ejected.

R

Z

R

ZEjected

Accreted

T/109K

0

4

8

Log(Density[g cm-3])864

Spherical

Ejected Accreted

High Velocity Fe Low Velocity O

6

4

2

02 4 6

Vz (/109cm s-1)

0.50.10.01

E51(=E/1051ergs)=10, MREM=6M, M(56Ni)=0.1M

16O56Ni(56Fe)

Fe, O Distribution

Vr

Relation in MREM and M(56Ni)

(M)

(M)

L Opt

ical

Efficient

e.g., rotation

inefficient

40M

20M

GW: GW:

Fe

MnO

Zn

Velocity Inversion of isotopes

V(Fe) > V(O), V(Zn) > V(Mn)

Spherical; Zn Fe Mn O

T , Inner (smaller V)

Ejection of heavier isotopes with higher V

Prediction

Jet (Z) Jet (R)

Spherical Jet (all direction)

O Fe and heavier

Spherical, 1052ergs, 0.1M Ni

Jet-Driven， 1052ergs, 0.1M Ni

O, MgMn

Co， Zn

Abundances in the whole ejecta

Possible Contribution to the early Galactic Chemical Evolution

Jet model: [Zn/Fe] ,[Mn/Fe]

Agrees with the abundances in old stars.

Past

[X/Y] = log(X/Y) – log(X/Y)

More Massive Star

-1

-0

.5

0

-1

-0

.5

0

[S/Si]

-0.6

-0

.4

-0.2

0

-0.6

-0

.4

-0.2

0

[Si/O]

40M25M

MBH/M

0 1 2 30 5 10

56Ni

S Si O

Accretion

Sph

Jet

Accretion

[S/Si],[Si/O]

0 5 10 0 1 2 3MBH/M-0

.2

0

0.2

0

.4

-0.2

0

0

.2

0.4

-1.4

-1

.2

-1

-0

.8

-1.4

-1

.2

-1

-0

.8

40M25M

[Mg/O]

[C/O]

O,Mg C

Accretion

Sph

Jet

Accretion

[Mg/O] ,[C/O]

Summary• The studies on hypernovae indicate;

– Velocity inversion of Fe and O – Dense core– Black hole formation

• Jet-induced explosions satisfy the above condition!– Blow up heavy isotopes (e.g., Fe, Zn) to the surface.– A black hole grows, with an energetic explosion.

• Possible site of gravitational wave emission?• Depending on angular momentum, HNe may be able to be detect

ed more easily than normal SNe.

– MBH efficiency of the jets (e.g., rotation?)

– MBH ( inefficient Jets) LOpt

– MBH Abundances (e.g., MBH [S/Si], [O/C] )