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Accreting black holes at low L/L Edd

Accreting black holes at low L/L Edd. Chris Done University of Durham. Truncated disc model at low L/L Edd. Spectral softness + PDS frequencies. Truncated disc/hot inner flow geometry very successful in explaining: Range of low/hard spectra Correlated change in PDS

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Accreting black holes at low L/L Edd

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  1. Accreting black holes at low L/LEdd Chris Done University of Durham

  2. Truncated disc model at low L/LEdd Spectral softness + PDS frequencies • Truncated disc/hot inner flow geometry very successful in explaining: • Range of low/hard spectra • Correlated change in PDS • Transition to soft state • Correlated collapse of jet • But still controversial… • Untruncated disc in LHS (very broad iron line, hot disc)? • TEST!! All hot inner flows (ADAF, ADIOS, CDAF) require protons have some (large) fraction of virial kT • Will get p + p p0 g+g

  3. Transitions: Cyg X-1 • Not much change in Lbol. Soft is disc dominated – radiatively eff, no hot flow so no p0 and would absorb anyway! • Hard state NOT disc dominated. Should have hot flow and hence p0 and absorption depth < 1 except for brightest hard states.

  4. Observable decays? • Thermal (ADAFs): Make X-ray spectrum! proton kT~1012-13 K (virial temperature). Electrons get energy from Coulomb collisions with protons and have kT ~ 109 K (100 keV). Get p0 (+ little sync. emission from the p+/-). • If non-thermal then have more above the p rest mass energy threshold so make more p0 (and relativistic p+/- ande+/-) Mahadevan, Narayan & Krolik 1997;Mahadevan 1999; Oka & Manmota 2003 Thermal Non Thermal Mahadevan 1999

  5. EGRET Egret already rules out nonthermal protons!! Must be thermal if p are heated…. Observable decays? If the protons are non-thermal then p+/- decay gives relativistic e+/- so get synchrotron as well as g rays from p0 – predicts non-thermal tail!!!! OSSE COMPTEL Mahadevan 1999 McConnell et al 2000

  6. Observable decays? OSSE COMPTEL EGRET Pretty close to constraining thermal models – GLAST!!! (30x better)

  7. Black holes • Appearance of BH should depend only on mass and spin (black holes have no hair!) • Plus mass accretion rate – L/LEdd • 104-1010 M: Quasars • 3-20 M: Galactic black holes

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