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Exploring Accreting Black Holes with Truncated Disc Models at Low L/LEdd by Chris Done

Learn about the successful use of truncated disc models in explaining low/hard spectra, PDS frequencies, and transitions to soft states in accreting black holes. Explore the controversial nature of untruncated discs and inner flow geometries. Discover insights into proton properties and transitions in black hole systems.

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Exploring Accreting Black Holes with Truncated Disc Models at Low L/LEdd by Chris Done

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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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