Feedback from MomentumDriven Winds Eliot Quataert UC Berkeley
Feedback from Momentum-Driven Winds Eliot Quataert (UC Berkeley) w/ Norm Murray & Todd Thompson NGC 3079 w/ HST
Outline • Context: Thermally-Driven Galactic Winds (supernovae) • Momentum-Driven Galactic Winds (radiation pressure) – Three Eddington Limits – Cosmological Speculation: Self-regulated Starbursts and BH Growth
The Standard Lore: Supernovae Driven Galactic Winds Hot gas blown out by collective effects of SN efficiency uncertain because most of SN energy deposited in ISM may be radiated away simulations suggest that little mass is blown away because SN vent their energy by ‘blowing out’ of the galactic plane Strickland & Stevens (2000)
Interaction of Cold Gas & Hot Wind Cold Clouds destroyed by hot wind Results probably underestimate destruction of cold gas (e. g. , no evaporation) unclear how to account for outflowing cold gas seen in absorption in LBGs, ULIRGs, local starbursts, etc. Poludnenko et al. 2002
Radiation Pressure Driven Winds • Dust absorbs the radiation produced by starbursts or AGN • Dust collisionally coupled to the gas: mfp ~ 10 a 0. 1 n 1 pc • Momentum-driven wind: • Efficient mechanism for blowing cold dusty gas out of a galaxy (i. e, couples to the phase of the ISM with most of the mass)
The Eddington Limit(s) • To blow gas out of galaxy, luminosity must exceed LEDD classic optically thin LEDD 2 2 = GM(r)/r ~ const • Optically Thick Clouds of Gas: Mass Mc Area Ac Mc/Ac ~ c. Rc ~ mp. NH Frad
Absorption-line Probes of Outflowing Cold Gas in Local Starbursts it im n. L gto n i d Ed Data from Heckman et al. (2000)
Terminal Velocity of Outflowing Cold Gas ULIRGs Dwarfs LIRGs Hot gas inferred to have Vhot ~ 500 km/s independent of Ram pressure in hot wind Vterm ~ Vhot ~ 500 km/s c rm ~ 2 . 5 ~ V es V te Data from Martin (2004) L ~ LEDD Vterm ~
Terminal Velocity of Outflowing Cold Gas interesting implications for enriching IGM, Ly- forest, etc. ULIRGs Dwarfs LIRGs c rm ~ 2 . 5 ~ V es V te Data from Martin (2004) small galaxies may preferentially lose more of their mass
The Optically Thick ‘Shell’ Limit (Galaxy Opaque Along Most Lines of Sight) M(r) = 2 2 r/G Mg = f. M For L > LM momentum injection is sufficient to blow away all of the gas in a galaxy Conjecture: LM is an upper limit to the luminosity of a starburst or AGN: systems that reach L M self-regulate & L does not increase further
The Maximum Luminosity of Starbursts
Decay of Starbursts Based on Models of Bruzual & Charlot (2003)
The Origin of the Faber-Jackson Relation? L L M 4 in high z starbursts such as LBGs, Scuba sources, … (probably in mergers) L LFJ as starburst fades
Black Holes • Efficient angular momentum transport in mergers can trigger BH growth and AGN activity 1/2 • Dust present outside Rsub ~ 1 L 46 pc • If L LM, AGN can blow dusty gas out of its vicinity, controlling its own fuel supply Josh Barnes
The Maximum Luminosity of Quasars from width of OIII line in NLR
The Origin of the M- Relation? 1/2 • Inside Rsub ~ 1 L 46 pc, dust destroyed • ‘Normal’ optically thin Eddington limit applies • With sufficient fuel supply, L ~ LEDD MBH • As BH grows, L LM 4
Summary • Radiation Pressure can drive powerful galactic winds and is an important feedback mechanism in the growth of galaxies & BHs • Can account for properties of cold outflowing gas seen in starbursts • Vterm ~ may modify picture of metal enrichment and impact of galactic winds on Ly- forest (winds less destructive …) 4 • LM ~ 3 x 1046 200 ergs/s: maximum luminosity of Galaxies & BHs? – may regulate mass of *s in early type galaxies (FJ) & mass of their central BHs (MBH- )
- Slides: 17