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

Strickland & Stevens (2000)

Hot gas blown out by collective effects of SN

efficiency uncertainbecause most of SN

energy deposited in ISMmay be radiated away

simulations suggest that little mass is blownaway because SN

vent their energy by‘blowing out’ of the

galactic plane

Interaction of Cold Gas & Hot Wind

Poludnenko et al. 2002

Cold Clouds destroyed by hot wind

Results probably underestimate destruction of cold gas

(e.g., no evaporation)

unclear how to account foroutflowing cold gas seen

in absorption in LBGs, ULIRGs,local starbursts, etc.

Radiation Pressure Driven Winds

• Dust absorbs the radiation produced by starbursts or AGN

• Dust collisionally coupled to the gas: mfp ~ 10 a0.1n1 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

• Optically Thick Clouds of Gas: Mass Mc

Area Ac

Frad

classicoptically thin LEDD

Mc/Ac ~ cRc ~ mpNH

22 = GM(r)/r ~ const

Absorption-line Probes of Outflowing Cold Gas in Local Starbursts

Data from Heckman et al. (2000)

Eddington Limit

Terminal Velocity of Outflowing Cold Gas

Data from Martin (2004)

V term ~ 2.5 ~ V esc

ULIRGs

LIRGs

Dwarfs

Hot gas inferred tohave Vhot ~ 500 km/s

independent of

Ram pressure in hot windVterm ~ Vhot ~ 500 km/s

L ~ LEDD Vterm ~

Terminal Velocity of Outflowing Cold Gas

Data from Martin (2004)

V term ~ 2.5 ~ V esc

ULIRGs

LIRGs

Dwarfs

interesting implicationsfor enriching IGM,Ly- forest, etc.

small galaxiesmay preferentially

lose more of their mass

The Optically Thick ‘Shell’ Limit(Galaxy Opaque Along Most Lines of Sight)

M(r) = 22r/G Mg = fM

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 LM

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 LM 4

in high zstarburstssuch as

LBGs, Scubasources, …

(probably in mergers)

L LFJ asstarburst fades

Black Holes

• Efficient angular momentum transport in mergers

can trigger BH growth and AGN activity

• Dust present outside Rsub ~ 1 L46 pc

• If L LM, AGN can blow dusty gas out of

its vicinity, controlling its own fuel supply

1/2

Josh Barnes

The Maximum Luminosity of Quasars

from width of OIII line in NLR

The Origin of the M- Relation?

• Inside Rsub ~ 1 L46 pc, dust destroyed

• ‘Normal’ optically thin Eddington limit applies

• With sufficient fuel supply, L ~ LEDD MBH

• As BH grows, L LM 4

1/2

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 …)

• LM ~ 3x1046 200 ergs/s: maximum luminosity of Galaxies & BHs?

– may regulate mass of *s in early type galaxies (FJ) & mass of their central BHs (MBH-)

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