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EXPLOSION OF VERY MASSIVE STARS AND THE ORIGIN OF INTERMEDIATE MASS BLACK HOLES

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.

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EXPLOSION OF VERY MASSIVE STARS AND THE ORIGIN OF INTERMEDIATE MASS BLACK HOLES

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  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. I. INTRODUCTION Supernovae and Chemical evolution of the universe Big Bang only H, He (metal-free) ? Metal? First Stars O,Mg,Si,Ca core-collapse SNe (massive) 1.37x1010 years Metal Mn,Fe,Co,Ni type Ia SNe (light) metal-rich universe Sun Earth present

  4. Final fate very-massive stars Our target Relativistic instability (super-massive star) Core-collapse Pair-Instability Supernova Core-collapse (SN II/Ib/Ic) White Dwarf (SN Ia) 105 300 8 140 stellar mass M Umeda & Nomoto 02 Heger & Woosley 02

  5. Formation of Very-Massive Stars First generation stars Halo, dark matter and gas accretion Radiation pressure is small in zero-metal environment cloud 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 proto star core very-massive (over 300M) ?

  6. Explosion of very-massive stars Does a core-collapse very-massive star (M>300M) explode? black hole But if it rotates BH Accretion disk Jet it may make a jet like explosion (GRB?) it may contribute to early chemical evolution

  7. Intermediate Mass Black Hole IMBH Super-massive BH (>106 M) Stellar mass BH (~10 M ) (IMBH, ~102 – 105 M) • Possible support: • 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. There 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 SMBH See, e.g., Rees, in this symposium Origin/Formation of IMBH Black hole

  9. (C) Direct Collapse, from halo See, 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 zero-age main sequence to Fe-core collapse (initial model for explosion, UV photon supply) Explosion hydrodynamical calculation 2 dimensional jet like explosion Nucleosynthesis comparison with observational abundance pattern

  11. Evolusionary track central temoperature central density

  12. Explosion 1000Mmodel (our result of evolution) Code･･･2D hydrodynamical code including gravity (Maeda & Nomoto 2003) explosion energy source･･･jet injection around BH dEjet/dt =(dMacc/dt) c2 BH Jet Disk : energy transformation efficiency (0.002 – 0.01) jet: jet angle(15o) initial BH mass…100M

  13. 5sec 100sec 50sec 10sec Snapshot of explosion(density structure) R/R*

  14. Abundance pattern and comparison with observational data ① CompareAbundance Pattern by nucleosynthesis with observational data (extremely metal-poor stars, M82 gas, intracluster matter, inter galactic medium) Link ? (very-massive star formation) black hole mass increases by accretion final black hole mass?

  15. Presupernova Composition 1000M Si He O He 56Ni Mg Fe-core is >20% p Ne p C ‘Fe’ For 25M Model, Fe-core is < 10% (Umeda & Nomoto 2003) Fe

  16. Abundance Pattern ε=0.0025; jet=15o ε=0.005; jet=15o ICM (intracluster matter) EMP (extremely metal-poor) stars Metal-poor stars ([Fe/H]< - 3) (Cayrel et al. 2004) [O/Fe] < 0 ,[Si/Fe] >0 : Consistent there is discrepancy in [O/Fe]

  17. M82 hot gas Gas composition in M82 (Origlia et al. 2004) 25M hypernova model Umeda & Nomoto (2002) Consistent rather than 25M hypernova model [O/Fe]~ - 0.3 [Ne/Fe]~0, [Mg/Fe]~ 0.3, [Si/Fe]~ 0.2 Black hole mass 500M… consistent with IMBH mass

  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 supply Log(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 evolving stars UV photon supply • Nreionize / Nb (Number of UV photon supply per baryon)~150 ( >> 10…necessary for reionization of IGM at z~4 ) Miralda-Escude&Rees 97 chemical contamination exploding star

  21. This work 1000M model…core-collapse very-massive stars 1056 this work Hypernova 1055 PISN 1054 normal SN 1053 Energy (erg) 1052 1051 10 100 1000 300 Initial Mass

  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

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