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Getting to Eddington and beyond in AGN and binaries!

Getting to Eddington and beyond in AGN and binaries!. Chris Done University of Durham. Accreting black holes. L / L Edd determined by mass accretion rate onto the black hole LMXRB – roche lobe overflow of low mass companion HMXRB – wind accretion from high mass companion

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Getting to Eddington and beyond in AGN and binaries!

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  1. Getting to Eddington and beyond in AGN and binaries! Chris Done University of Durham

  2. Accreting black holes • L/LEdd determined by mass accretion rate onto the black hole • LMXRB – roche lobe overflow of low mass companion • HMXRB – wind accretion from high mass companion • HMXRB – roche lobe overflow from high mass companion • AGN

  3. Accreting black holes • L/LEdd determined by mass accretion rate onto the black hole • LMXRB – roche lobe overflow of low mass companion • HMXRB – wind accretion from high mass companion • HMXRB – roche lobe overflow from high mass companion • AGN

  4. Accreting black holes • L/LEdd determined by mass accretion rate onto the black hole • LMXRB – roche lobe overflow of low mass companion • HMXRB – wind accretion from high mass companion • HMXRB – roche lobe overflow from high mass companion • AGN

  5. Accreting black holes • L/LEdd determined by mass accretion rate onto the black hole • LMXRB – roche lobe overflow of low mass companion • HMXRB – wind accretion from high mass companion • HMXRB – roche lobe overflow from high mass companion • AGN

  6. LMXRB – Transient! • H ionisation instability in disc – eg Lasota 2001 • If T(Rout)<H ionisation then disc globally unstable • T(Rout) depends on mass, mass accretion rate and binary size – all correlated by roche lobe overflow condition! DGK07 2 years

  7. Roche lobe overflow • Radius of star depends on type (ie mass) • Star has to fill roche lobe for mass accretion • Mass accretion rate from companion depends on type • Outer edge of disc can’t be larger than ½ size of binary orbit. • Find all have T(Rout)<H ionisation instability for all low mass companion stars • See review by Lasota (2001) Menou et al 1999

  8. Roche lobe overflow • Peak luminosity depends on how much mass can accumulate in quiescence and how fast it accretes onto black hole • Lpeak  R(out)3/R(out )  R(out)2 King & Ritter 1998 • Main sequence secondary is small so R(out) small so Lpeak<LEdd

  9. LMXRB BH in our galaxy J. Orosz • GRS1915+105 is huge! 33 day period. L/LEDD~1 for 20 years • GS2023 – went to 2LEdd, then blew its disc apart… • GX339 and XTEJ1550 are the next biggest but L<LEDD

  10. Winds fed HMXRB – BH • Rare systems – most end as NS in population synthesis models • High mass loss rate from stellar wind, but only capture small fraction so L<<LEdd

  11. Roche lobe overflow HMXRB-BH • Main sequence high mass star. Mass accretion rate from companion is high • Keeps outer disc temperature in Cyg X-1 above H ionisation so persistent • HUGE mass transfer as supergiant evolves – SS 433 in our galaxy • Most ULX in other galaxies

  12. Roche lobe overflow HMXRB-BH • Main sequence high mass star. Mass accretion rate from companion is high • Keeps outer disc temperature in Cyg X-1 above H ionisation so persistent • HUGE mass transfer as supergiant evolves – SS 433 in our galaxy • Most ULX in other galaxies Rappaport et al 2005

  13. Intermediate mass BH? • Ultra - Luminous X-ray sources in spiral arms of nearby starforming galaxies – ULX • L~1039-40 ergs s-1so M~10-100 Mfor L <LEdd • Hard for stellar evolution to make BH > 50 M Gao et al 2003

  14. ULX state ? • Hard spectra plus soft excess looks like scaled up BHB in LHS? • IMBH? • But break above 7keV – NOT like LHS!!! Gladstone Roberts & Done 2008

  15. ULX state ? Gladstone Roberts & Done 2008

  16. ULX state ? Gladstone Roberts & Done 2008

  17. ULX state ? Gladstone Roberts & Done 2008

  18. AGN • L/LEdd determined by mass supply • But ~0.5% of mass in star formation ends up in the black hole to make the M-s relation

  19. BH-Galaxy AND environment • Big black holes live in host galaxies with big bulges! • Need 0.5% of bulge mass (iestarformation) to end up down the BH 109 Black hole mass 103 Stellar system mass 106 1012

  20. Black hole mass Fanidakis et al 2010 • SMBH grow by gas accretion and BH-BH mergers • Mergers dominate only highest BH mass (> 109 M) . Spin of 0.7-0.8 • Accretion (thin disk) dominates for lower mass (<108 M) • Accretion (hot flow) never really dominates

  21. Black hole mass accretion rate Fanidakis et al 2010 • Not many with L/LEdd>1 in local universe - and they are predominantly low mass BH • What do they look like?

  22. Disc spectra from 106 M L/LEdd ~1 Jin et al 2011 • Much more soft X-ray flux than expected from either disc or power law • Enormous soft X-ray excess !!

  23. Disc spectra from 106 M L/LEdd ~1 Done, Davis, Jin, Blaes Ward 2011 • Standard SS disc temperature – assumes energy thermalises • BHB discs - Colour temperature correction as scattering > absorption opacity. Tobs=1.8 Teff • AGN discs even more scattering dominated as less dense !! Factor 2.4 !!

  24. Disc spectra from 106 M L/LEdd ~1 Done, Davis, Jin, Blaes Ward 2011 • Enourmous soft excess in REJ1034 • But actually a lot of it should be the bare disc! • Plus a little bit of comptonisation ! • More like disc dominated black holes

  25. Conclusions • Galactic BHB can’t get to Eddington very easily • Exceptions are LMXRB in wide binaries with evolved companions – GRS1915+105 • And HMXRB evolving into supergiants – SS 433 and probably ULX. • And some nearby low mass high mass accretion rate AGN like REJ1034 (QPO AGN). • Disc in these AGN MUST extend into soft X-rays. Much of soft X-ray excess in these is the bare disc. Then need SMALL comptonisation to get shape of component

  26. Unsolved problems • How does magnetic field stress dissipate and heat the accretion flow? Can we get as high as a~0.1? Stress HEATS so eventually gives pressure so alpha prescription OK on average?? • What happens to the disc as we go to Eddington and beyond? • How does it stay optically thick up to ~0.5LEdd? • How important are winds Fgrav=(1- kabs/kes L/LEdd) GM/R2 • How important is advection of radiation – and what fraction of this escapes from the plunging region becoming optically thin: not radiatively inefficient? • How does the B field manage to get the same (approx) vertical flux to launch the same power jet in lots of different BHB? • How does thin cool disc truncated into hot flow? Simulations?? • what are the HF QPOs ? • method for measuring a*? But LF QPOs probably don’t !!!! • Can we understand iron line profiles ? And get all methods for measuring a* giving the same answer?

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