explosion of very massive stars and the origin of intermediate mass black holes
DESCRIPTION
EXPLOSION OF VERY MASSIVE STARS AND THE ORIGIN OF INTERMEDIATE MASS BLACK HOLES. S. Tsuruta, T. Ohkubo, H. Umeda, K. Maeda, K. Nomoto, T. Suzuki, and M.J. Rees. IAU Symposium 238, Prague. Czech, August 24, 2006. CONTENT. I. INTRODUCTION II. OUR RECENT RESEARCH III. SUMMARY/CONCLUSION. - PowerPoint PPT PresentationTRANSCRIPT
1
EXPLOSION OF VERY MASSIVE STARS AND THE
ORIGIN OF INTERMEDIATE MASS BLACK HOLES
S. Tsuruta, T. Ohkubo, H. Umeda, K. Maeda, K. Nomoto, T. Suzuki, and M.J. Rees
IAU Symposium 238, Prague. Czech, August 24, 2006
2
CONTENT
I. INTRODUCTION
II. OUR RECENT RESEARCH
III. SUMMARY/CONCLUSION
3
Supernovae and Chemical evolution of the universeBig Bang
core-collapse SNe (massive)
type Ia SNe (light)
O,Mg,Si,Ca
only H, He (metal-free)
Mn,Fe,Co,Ni
present Sun Earth
Metal?
metal-rich universe
First Stars?
Metal1.37x1010
years
I. INTRODUCTION
4
Final fate very-massive stars
Pair-Instability Supernova
Core-collapse
8 140 300 105
White Dwarf(SN Ia)
Core-collapse(SN II/Ib/Ic)
Relativistic instability(super-massive star)
stellar mass MUmeda & Nomoto 02Heger & Woosley 02
Our target
5
Formation of Very-Massive Stars First generation stars
very-massive (over 300M) ?
cloud
proto star core
Radiation pressure is small in zero-metal environment
Proto star core can grow larger
Rees, Madau, in this symposium
Omukai & Palla 2003; Abel et al. 2002;
Tan & McKee 2004; Bromm & Loeb 2004;
Ohkubo et al. 2006, in preparation
Halo, dark matter and gas accretion
6
Explosion of very-massive starsDoes a core-collapse very-massive star (M>
300M) explode?
black holeBut if it rotates
it may make a jet like explosion (GRB?)it may contribute to early chemical evolution
BHAccretion diskJet
7
Intermediate Mass Black Hole
Stellar mass BH (~10 M ) IMBH Super-massive BH
(>106 M )
(IMBH, ~102 – 105 M)
Possible support: (1) ULX in M82 > ~ 700 M, etc., see Makishima, Mushotzky in this symposium
(2) Galactic Center: see, e.g., Genzel, etc., in this symposium
(3) Smallest Black Holes in AGNs:IMBH may be found by search of smallest black holes throguh AGN survey, using the
relation between the host galaxy and central black hole, – e.g., the extention of the σ-black hole mass relation for SMBH to lowest masses (small Seyferts, dwarf galaxies, etc.)
See, e.g., Barth et al. in this symposium
8
Origin/Formation of IMBHThere are many possible ways
(A) If very-massive stars exist
they may be the origin of IMBH !! This talk, Ohkubo et al. 2006
(B) Intermediate stages from seed BH to SMBHSee, e.g., Rees, in this symposium
Black hole
9
(C) Direct Collapse, from haloSee, e.g., Begelman, et al. 2006
(D) Successive merger of stars in a dense cluster: e.g., Portegies et al. 2004
Very-massive star (M>300M)
IMBH
10
II. OUR RECENT RESEARCHOhkubo et al. ApJ, 645, 1352, July 10, 2006
Evolution
Explosion
Nucleosynthesis
zero-age main sequence to Fe-core collapse
(initial model for explosion, UV photon supply)
hydrodynamical calculation
2 dimensional jet like explosion
comparison with observational abundance pattern
11
Evolusionary track ce
ntra
l tem
ope
ratu
re
central density
12
ExplosionExplosion
dEjet/dt = (dMacc/dt) c2
jet: jet angle(15o)
initial BH mass…100M
: energy transformation efficiency (0.002 – 0.01)
1000M model (our result of evolution)Code ・・・ 2D hydrodynamical code including gravity (Maeda & Nomoto 2003) explosion energy source ・・・ jet injection around BH
BHJetDisk
13
Snapshot of explosion (density structure)
5sec 10sec
50sec 100sec
R/R
*
14
Abundance pattern and comparison with observational data
Compare Abundance Pattern by nucleosynthesis with observational data
(extremely metal-poor stars, M82 gas, intracluster matter, inter galactic medium)
black hole mass increases by accretion
final black hole mass?
①
(very-massive star formation)Link ?
15
Presupernova Composition
p
He
Fe
Si O
Ne
C
Mg56Ni
‘Fe’
p
He
1000M
For 25M Model, Fe-core is < 10%
(Umeda & Nomoto 2003)
Fe-core is >20%
16
Abundance Patternε=0.0025; jet=15o
Metal-poor stars ([Fe/H]< - 3) (Cayrel et al. 2004)
there is discrepancy in [O/Fe]
[O/Fe] < 0 ,[Si/Fe] >0 : Consistent
EMP (extremely metal-poor) stars
ICM (intracluster matter)ε=0.005; jet=15o
17
M82 hot gas
Gas composition in M82
(Origlia et al. 2004)
[O/Fe]~ - 0.3
[Ne/Fe]~0, [Mg/Fe]~ 0.3, [Si/Fe]~ 0.2
Black hole mass 500M … consistent with IMBH mass
25M hypernova model
Umeda & Nomoto (2002)
Consistent rather than 25M hypernova model
18
• IGM (inter galactic medium) (redshift z:2~4.5)
• Observation: [C/Si] <~ - 0.5 (Aguirre et al. 2004)
• Yields by PISNe: [C/Si] ~ - 2.0 to - 1.7• Our 1000M yields: [C/Si] ~ - 0.78 to - 0.65
Consistent in order of magnitude with observational ratio
19
UV photon supplyLog(Teff) ~ 5.05 (4.85 – 5.0 for Pop III 15 – 90M stars)
(Tumlinson & Shull 2000)
Ionizing photons (/s/M)
H I : 1.6 × 1048 (16 times higher)
He I : 1.1 × 1048 (14 times higher) He II: 3.8× 1047 (75 times higher ) than by Salpeter IMF (values with a Salpeter IMF)
20
UV photon supply and chemical contamination
• Nreionize / Nb (Number of UV photon supply per baryon) ~150
( >> 10…necessary for reionization of IGM at z~4 )Miralda-Escude&Rees 97
UV photon supplyevolving stars
exploding star chemical contamination
21
This work
normal SN
Hypernova
PISN
this work
Initial Mass
Ene
rgy
(erg
)
10 100 1000
1051
1052
1053
1054
1055
1056
300
1000M model…core-collapse very-massive stars
22
III. Summary/CONCLUSION
(i) 1000M stars …UV photons efficiently supplied
(ii) Final black hole is ~ 500M
…consistent with IMBH mass
(iii) Abundance pattern
…consistent with M82 gas, ICM, IGM