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Hypercritical Accretion around Neutron Stars & Black Holes

BH2006@APCTP. Hypercritical Accretion around Neutron Stars & Black Holes. Bethe, Brown, Lee, … ApJ 541 (2000) 918 New Astronomy 6 (2001) 331 ApJ 575 (2002) 996 PASJ 56 (2004) 347 astro-ph/0510379. Chang-Hwan Lee. Hypercritical Accretion onto Neutron Star ?.

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Hypercritical Accretion around Neutron Stars & Black Holes

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  1. BH2006@APCTP Hypercritical Accretionaround Neutron Stars & Black Holes Bethe, Brown, Lee, … ApJ 541 (2000) 918 New Astronomy 6 (2001) 331 ApJ 575 (2002) 996 PASJ 56 (2004) 347 astro-ph/0510379 Chang-Hwan Lee

  2. Hypercritical Accretion onto Neutron Star ? In the formation of NS in SN1987AHypercritical Accretion ( 108 Eddington Limit) occurred. Otherwise NS couldn’t be formed at all ! Thermal Neutrinos are responsible (T>1 MeV) ! Hypercritical Accretion onto Black Holes ? No surface: Trapped photons ? Ultra Luminous X-ray Sources ?

  3. Plan of Talk Focused on Binary Evolution Implications of Hypercritical Accretion onto BH Possible connection between BH Binaries (Soft X-ray Transitions) & ULXs Implications of Hypercritical Accretion onto NS LMBH-NS Binaries as sources of LIGO

  4. Motivations Observations: Soft X-ray Transients

  5. Soft X-ray Transients Black Hole Binaries in our Galaxy Galactic Disk XTE J1118+480

  6. X-ray & Optical Telescopes Oscillating Brightness (GRO J1655-40)

  7. Q) How can we understand the population of SXTs ? 15 MBH (Msun) 10 Evolved companion 5 MS companion 1 10 Orbital period (days)

  8. Soft X-ray Transients Mass Transfer Processes in the Evolution of Black Hole Binaries

  9. Evolution of BH Progenitor Phase I Goal : At the time BH Formation Phase II Evolution of Donor Star Current Observation

  10. Phase I High Mass Black Hole progenitor (20-40 Msolar) Bigger star evolves fast ! High Mass Black Hole is formed when the separation is large (meet at supergiant stage) NS/LMBH is formed when the separation is relatively small (meet at/before red giant stage)

  11. Fe core mass Neutron Star In Close Binaries

  12. Phase I C HMBH NS/LMBH B A

  13. Phase I Mass gap between observed NS & BH ? HMBH (5-10 Msun) NS/LMBH (< 2 Msun)

  14. Phase I Common Envelope Evolution Efficiency Binding Energy in the Envelope of BH progenitor Change of Energy of Binary Orbital Motion Efficiency

  15. Q) Can we get informations on the efficiency ? Evolved companion V4641 Sgr 15 MBH (Msun) 10 5 4U1543-47 Nova Sco 1994 1 10 Orbital period (days)

  16. Phase I o : Schaller et al.

  17. Phase I

  18. Phase I 6 Msun Companion Not much orbital evolution after formation

  19. Phase I Phase I Phase II

  20. Phase I 2 Msun Companion Phase II Phase I

  21. Phase I Formation of Rotating Black Holes Assumption Case C Mass Transfer (in supergiant stage of BH progenitor) Common Envelope Efficiency 0.2 If BH formation through Case B (in giant stage) is possible, contrary to the observation, we should see 20 times more BHs in our Galaxy.

  22. Phase I NS LMBH HMBH Formation in Case C HMBH Phase II Current 1915+105(108 Rsun)

  23. At the time BH Formation Black Hole Binaries/Hyernovae/GRB Assumption: Synchronization of BH-Progenitor Spin & Binary Orbital Period Rapidly rotating BH with large Kerr parameter (even close to 1) SXTs with short orbital periods Possible sources of Hypernovae/GRB

  24. At the time BH Formation Kerr parameter Preexplosion orbital period (days)

  25. At the time BH Formation Gamma Ray Bursts from Black Hole Systems • Energy > 1051 ergs • Rinit = O(100 km) • M < 30 Msun • dT = ms – min • …… Most likely BHs ! BH Binary is natural source of rapidly rotating black hole Energy in Hypernovae = Energy in GRBs BH Binaries -> Long Time Scale GRBs (> 2 sec)

  26. Phase II Evolution of BH Binaries with after Birth Evolution after BH formation Life time of donor [Morig, Mlost]

  27. Phase II Shrink Evolved Companion Expand MS companion I: Hubble TimeII: Main SequenceIII: Oveflow at t=0 AML: Angular Mom Loss Nu: Nuclear Burning

  28. Phase II Current Observation

  29. At the time BH Formation Reconstructed BH Binaries at Birth BH Spin – 10000/sec HN/GRB

  30. Phase II vs ULXs OK 15 Msun ? 10 Msun Q) How to Evolve ?

  31. Q) How to form BHs in 10-15 Msun ? problem 1:It’s hard to form BH with masses > 10 Msun from stellar evolution. problem 2:The current separation is too large. easiest solution: Accrete extra mass after BH formation

  32. Phase II ?

  33. Phase II vs ULXs Conservative Mass Transfer V4641 Sgr Data: 33.5 days 2.817 days GRS 1915+105 Consistent within error range

  34. Phase II vs ULXs Soft X-ray Transients 33day 14 Msun + 2 Msun 3day 15 Msun 9.5 Msun + 6.5 Msun 10 Msun 1915+105 V4641 Sgr Beauty of Simple Physical Laws !

  35. Phase II vs ULXs Pre-Explosion Properties V4641 & 1915

  36. Phase II vs ULXs Q) How mass is transferred from Donor to BH ?

  37. Phase II vs ULXs Evolution of Donor R/Rinitial Burning State

  38. Phase II vs ULXs Evolution of Donor R/Rinitial t/tlife

  39. Phase II vs ULXs Mass Transfer Rate from Donor to BH Q) 100 Eddington Limit ?

  40. Phase II vs ULXs Eddington Luminosity & Mass Accretion Rate LEdd = 1.3 x 1038 (M/Msun) erg/s Spherical Accretion L = f GMdM/R If f=1 & L=LEdd dM = dMEdd

  41. Phase II vs ULXs Ultra Luminous X-Ray Sources LEdd = 1.3 x 1038 (M/Msun) ergs/s

  42. Phase II vs ULXs Ultraluminous X-ray Sources • Original Claim Discovery of Intermediate Mass BH ( > 100 Msun ) cf) dominant BH : stellar => 10 Msun galactic => 106-109 Msun • Problem Too Many of them Hard to evolve them • Question: Then, what are they ?

  43. Phase II vs ULXs SXTs (10 Msun BH) with evolved companions => 100 Eddington Mass Accretion Rate LLimit = N LEdd N = O(10) : Porous Disk [white dwarf] => 10 Msun BH can explain the ULXs ! LLimit = f GMdM/R f = O(0.1) : Photon Trapping dM =100dMEdd 10 Msun BH can have 10 LEdd & 100 dMEdd

  44. Phase II vs ULXs Ultra Luminous X-Ray Sources LLimit = 10 LEdd= 13 x 1038 (M/Msun) ergs/s

  45. Phase II vs ULXs SXTs with initial heavy companion ULXs (0 degree) L > 10 LEdd GRS 1915+105 (70 degree) L = LEdd 10 Msun BH + 6 Msun Companion

  46. Conclution: Hypercritical Accretion onto BH • Population of Soft X-ray Transients can be understood by considering various mass transfer processes. • Some of ULXs may be related with SXTs with evolved companions (higher mass companions)

  47. Hypercritical Accretion onto NS LMBH-NS Binaries: Implications for LIGO Science 308 (2005) 939

  48. Gravitation Wave from Binary Neutron Star B1913+16 Hulse & Taylor (1975) Effect of Gravitational Wave Radiation 1993 Nobel PrizeHulse & Taylor

  49. Evolution of binary NS <1% A Life time 10% B 90% He H red giant super giant Original ZAMS(Zero Age Main Sequence) Stars • Probability = 1/M2.5 • Life Time = 1/M2.5 • DM=4%, DTlife=(1 - 1/1.042.5)= 10%, DP=10% (population probability)

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