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Exploring the Connection Between Ultraluminous X-ray Sources and Soft X-ray Transients

This study investigates the potential relationship between Ultraluminous X-ray Sources (ULXs) and Soft X-ray Transients (SXTs). It discusses the implications of mass accretion in neutron stars and black holes (NS/BH), emphasizing Eddington luminosity and mass accretion rates. The research examines how accretion may occur through mechanisms such as fallback after supernova explosions and interactions with companion stars. The findings suggest that ULXs could be black hole binaries similar to SXTs, influenced by photon trapping effects and conservative mass transfer dynamics.

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Exploring the Connection Between Ultraluminous X-ray Sources and Soft X-ray Transients

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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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