Feedback from Momentum-Driven Winds

1
Feedback from Momentum-Driven Winds Eliot
Quataert (UC Berkeley) w/ Norm Murray Todd
Thompson
NGC 3079 w/ HST
2
Outline

• Context Thermally-Driven Galactic Winds
  (supernovae)
• Momentum-Driven Galactic Winds (radiation
  pressure)
• Three Eddington Limits
• Cosmological Speculation Self-regulated
  Starbursts and BH Growth

3
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)
4
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
5
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)

6
The Eddington Limit(s)

• To blow gas out of galaxy, luminosity must exceed
  LEDD
• Optically Thick Clouds of Gas Mass Mc
• Area Ac

classic optically thin LEDD
2?2 GM(r)/r const
Frad
Mc/Ac ?cRc mpNH
7
Absorption-line Probes of Outflowing Cold Gas in
Local Starbursts
Eddington Limit
Data from Heckman et al. (2000)
8
Terminal Velocity of Outflowing Cold Gas
Hot gas inferred to have Vhot 500
km/s independent of ? Ram pressure in hot
wind Vterm Vhot 500 km/s L LEDD ? Vterm
?
ULIRGs
Dwarfs
LIRGs
Vterm 2.5 ? Vesc
Data from Martin (2004)
9
Terminal Velocity of Outflowing Cold Gas
interesting implications for enriching IGM, Ly-?
forest, etc. small galaxies may
preferentially lose more of their mass
ULIRGs
Dwarfs
LIRGs
Vterm 2.5 ? Vesc
Data from Martin (2004)
10
The Optically Thick Shell Limit(Galaxy Opaque
Along Most Lines of Sight)
M(r) 2?2r/G Mg fM
For L gt 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
11
The Maximum Luminosity of Starbursts
12
Decay of Starbursts
Based on Models of Bruzual Charlot (2003)
13
The Origin of the Faber-Jackson Relation?
L ? LM ? ?4 in high z starbursts such as LBGs,
Scuba sources, (probably in mergers) L ? LFJ
as starburst fades
14
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

Josh Barnes
1/2
15
The Maximum Luminosity of Quasars
? from width of OIII line in NLR
16
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
17
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-?)

4