ハイパーノバとブラックホール Hypernovae 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, Department of Astronomy SN 1998bw SN 1987A = E ~ 30×1051ergs E ~ 1×1051ergs Hypernova Candidates Ekinetic > (5-10)×1051ergs SNe Ic SN GRB SNe IIn SN GRB 1998bw 980425 1997cy 970514 1997ef 1999E 980910 971115 1999as 1988Z 2002ap 1999eb 1997dq 1998ey 1992ar SN 1998bw 991002 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? 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 j~1017cm2s-1 j~1016cm2s-1 M~1M R ~100km at Bounce J Conserve SN at 10Mpc (1SN/year); f~100 Hz, h~4×10-23 MDISK~2M R ~100km J Conserve HN at 100Mpc (1HN/year); f~1000 Hz, h~8×10-22 Spectra of Supernovae & Hypernovae Ic: no H, Ia Ib SiII O Ca He Ic Hyper -novae no strong He, 94I 97ef 98bw no strong Si Hypernovae： broad features blended lines “Large mass at high velocities” Light Curves of Supernovae & Hypernovae Light Curve Broadness SN1998bw >> SN1994I Ejected Mass SN1998bw >> SN1994I Progenitor’s Mass SN1998bw >> SN1994I CO Star Models for SNeIc Parameters [Mej, E, M(56Ni)] H-rich He Light Curve ５６Fe C+O MC+O Si Fe Mms/M 56Co 56Ni Collapse MC+O/M ~ 40 13.8 ~ 35 11.0 ~ 22 5.0 Spectra ~ [dyn • diffusion]1/2 E Mej Mej 1/2 R ~ V • Rc ½Mej¾E E Mej3 -¼ ５６Ni 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 • 1 HN per 1 year in R<100Mpc. • 1 SN per 1 year in R<10Mpc. 10 100 Mpc Hypernova Rate Local SN Rate (SN/100yr/1010L) h=H0/100 Corrected1) Observed2) Ia Ib/c II All 0.36±.11h2 0.14±.07h2 0.71±.34h2 1.21±.36h2 111 18 54 183 1)Cappellaro et al. 99, 2)Richardson et al. 01 HNIb/c SNIb/c N(20M-50M) = 3(+1+2)/18 N(8M-20M) ~ 0.3 (Salpeter IMF) ~ 0.15 – 0.3 • Large Fraction of Massive O (or He) Star with M>20M Explodes as Hypernovae. Depending on Binary Evolution? Properties of Hypernova Explosions (1) Deviation from spherical explosion models (2) Black hole formation 1) Asphericity in Core-collapse SNe (in general) SN1987A: Asymmetrical, but not spherical, ejecta Optical Polarization in core-collapse SNe > 0.5 % (in SNe Ia < 0.2 - 0.3%) HST Image of SN1987A Optical Spectropolarimetry of Wang et al. 2002 SNe 1993J, 1996cb, Wang et al. 1999 2) Light Curves of Hypernovae 1998bw 1998bw 1997ef 1997ef 2002ap 2002ap Low Density (Vacuum) Spherical Hydro Model High Density Maeda et al. 2003, ApJ, submitted 3) Late time spectra of SN1998bw Line Width Inversion between Fe and O [OI] 6300A O Fe FWHM Observation FeII] 5200A Spherical Expansion Observer Broader Fe lines than O lines in the observations. Low velocity O-rich Matter: SNe1998bw, 1997ef Interpretation as an Aspherical explosion [OI] 6300A Observation FeII] 5200A Spherical 56Fe 15 deg 16O Aspherical Maeda et al. 2002 4) BH Formation Abundances in Nova Sco [X/H]=log10(X/H)-log10(X/H) 1.5 SN matter [X/H] 1 BH 0.5 0 N O Mg Si S Ti Fe -0.5 • Enhancement of O,Mg,Si,S,Ti by a factor of 6-10. Israelian et al. 1999 Hypernova model for the formation of the BH in Nova Sco Abundance in Nova Sco 1 E51=30 [X/H] 0.8 0.6 BH mass in the model 4.8M at the explosion SN 0.4 0.2 0 He C O Ne Mg Si S Ca Ti Fe 5.4M now (Post 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? Model: Jet-induced Explosion MRem0 1.0 – 3.0M 16MHe (MMS=40), 8M He (MMS=25), (Nomoto&Hashimoto 1988) Radiation＋Pairs 15o Newtonian Gravity Ejet = Mc2 , 0.01 Postprocessing 222 isotopes (Tielemann et al.) K. Maeda, in preparation Log (Density[g cm-3]) Hydrodynamics Radial Velocity/c Collimated jets (Z) + Bow shock (All direction) M Lateral expansion R/1010cm Density Hydrodynamics (Center) Accretion from the side Continue to accrete, MBH Radial Velocity R/1010cm E51=11, MBH(final)=5.9M, M(56Ni)=0.11M Outflow Inflow 0.7 s 1.5 s R/1010cm Density Distribution High density core at the central region High velocity material along z Jet (R) Sph (E51=1) Sph (E51=10) Jet (z) (E51=11) Growth of a central remnant MBH Inefficient Jet 8 MREM can be ~ 5 – 10M, starting from 1.5 – 3M. Still a strong explosion follows (E51>10). efficient Jet 4 0 20 40 Time (sec) A hypernova with a stellar mass black hole (X-ray Novasco; Large Si,S with black hole formation). Final Remnants’ masses and Kinetic Energies 11 6.9 5.9 E51 =E/1051ergs 1.9 MBH(M) • A more massive star makes a more energetic explosion (As seen in ‘Hypernova Branch’). Peak Temperature & Density T/109K 8 Z Z Ejected 4 R Accreted 0 R Spherical Ejected 4 6 Accreted 8 • High T + Low Material are preferentially ejected. Log(Density[g cm-3]) Fe, O Distribution Vz (/109cm s-1) 6 E51(=E/1051ergs)=10, MREM=6M, M(56Ni)=0.1M 4 2 0 High Velocity Fe 2 4 Low Velocity O 6 Vr 0.5 0.1 56Ni(56Fe) 16O 0.01 (M) LOptical Relation in MREM and M(56Ni) 40M 20M Efficient GW: e.g., rotation (M) inefficient GW: Velocity Inversion of isotopes Fe Zn O V(Fe) > V(O), V(Zn) > V(Mn) Spherical; Zn Fe Mn O T , Inner (smaller V) Mn Prediction Ejection of heavier isotopes with higher V Jet (Z) Jet (R) O Spherical Fe and heavier Jet (all direction) Abundances in the whole ejecta Spherical, 1052ergs, 0.1M Ni O, Mg Mn Co，Zn Jet-Driven，1052ergs, 0.1M Ni Possible Contribution to the early Galactic Chemical Evolution [X/Y] = log(X/Y) – log(X/Y) Past More Massive Star Jet model: [Zn/Fe] ,[Mn/Fe] Agrees with the abundances in old stars. 56Ni 0 0 [S/Si] -0.5 -0.5 Sph -0.6 -0.4 -0.2 -1 25M 0 10 1 MBH/M 2 3 0 5 0 [Si/O] 0 40M Accretion Accretion [S/Si],[Si/O] -0.6 -0.4 -0.2 -1 Jet S Si O 0.4 0.4 [Mg/O] ,[C/O] 5 -0.2 0 1 MBH/M 2 3 -1 -0.8 -1 10 25M -0.8 0 -1.4 -1.2 [C/O] 40M Accretion Jet Sph -1.4 -1.2 -0.2 0 0 [Mg/O] 0.2 0.2 Accretion O,Mg C 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 detected more easily than normal SNe. – MBH – MBH – MBH efficiency of the jets (e.g., rotation?) ( inefficient Jets) LOpt Abundances (e.g., MBH [S/Si], [O/C] )
© Copyright 2024 ExpyDoc
