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Possible Connection between ULXs and SXTs

Possible Connection between ULXs and SXTs. Chang-Hwan Lee Seoul National University. 2002.11.29 KIAS. Why do we consider Accretion in NS/BH ? Eddington Luminosity & Mass Accretion Rate Ultraluminous X-ray Sources (ULXs) ULXs from Soft X-ray Transients Conclusion.

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Possible Connection between ULXs and SXTs

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  1. Possible Connection between ULXs and SXTs Chang-Hwan Lee Seoul National University 2002.11.29 KIAS

  2. Why do we consider Accretion in NS/BH ? • Eddington Luminosity & Mass Accretion Rate • Ultraluminous X-ray Sources (ULXs) • ULXs from Soft X-ray Transients • Conclusion

  3. Why do we consider accretion in NS/BH ? • Accretion by Fallback after SN Explosion • SN 1987A : NS/BH was covered by material for a few years • Numerical Calculation [a few solar mass can accrete] • Accretion by Companion Star • Missing Ingredient in SN explosion • Rotation • Binary provide natural rotation by tidal interaction • NS/BH accrete matter from companion

  4. 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

  5. Ultra Luminous X-Ray Sources LEdd = 1.3 x 1038 (M/Msun) ergs/s

  6. 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 ?

  7. Soft X-ray Transients 15 Msun 10 Msun Q) How to evolve ?

  8. C B A

  9. HMBH NS/LMBH

  10. HMBH formation in Case C HMBH NS LMBH Current 1915+105 (108 Rsun)

  11. Pre-Explosion Properties ApJ 575 (2002) 996 V4641 & 1915

  12. Conservative Mass Transfer V4641 Sgr Data: 33.5 days 2.817 days GRS 1915+105 Consistent within error range

  13. 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 !

  14. Accretion Rate from V4641 Sgr to 1915+105 Coservative Mass Transfer

  15. 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 =100 dMEdd 10 Msun BH can have 10 LEdd & 100 dMEdd

  16. Ultra Luminous X-Ray Sources LLimit = 10 LEdd= 13 x 1038 (M/Msun) ergs/s

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

  18. Conclusion • ULXs may be BH binaries similar to SXTs in our Galaxy. • LLimit = 10 LEdd • We predict efficiency f=O(0.1) with photon trapping based on the evolution from V4641 Sgr to 1915+105. • dM = 100 dMEdd

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