Stellar & AGN Feedback in
Galaxies
GLCW8 Columbus 2007
Evidence for Feedback
(Self-limited Star Formation?)
Krabbe et al
astro-ph/0703804
Mb~3
M*~4
Inefficient Star Formation-Feedback?
Kennicutt 1998
Ý*  ;   0.017


Implies same physics over 4 decades in gas
Evidence for Feedback: Windssignificant mass & momentum in cold gas
e.g., Heckman et al. 00;
Martin 04,05
M82 (Subaru)
Evidence for Feedback
(self-limiting BH accretion?)
Greene & Ho 05
Large-Scale Feedback
Fabian et al (2006)
Perseus Cluster
Large-Scale Feedback
Fabian et al (2006)
Perseus Cluster
Feedback Mechanisms
• Energy Input
– Stars (local)
• SN
• HII
• Winds
– AGN
• Via Radiation
• Jets (large scale)
• Winds (Broad Absorption Line QSOs)
• Momentum Input
– Stars
• SN
• Radiation
– AGN
• Radiation
Radiation Pressure Feedback
• Dust absorbs the radiation produced by starbursts or AGN
• Dust collisionally coupled to the gas: mfp ~ 1 a0.1n1 pc
• Starlight provides turbulent pressure support ·of ISM
• Momentum-driven wind: V∞ ~ Vc
·
·
·
L/c @ MWV∞
·
L ~ 10-3 M*c2 ~ MWV∞c  MW ~ M*
• 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)
Terminal Velocity of Outflowing Cold
Gas
Hot gas inferred to
have Vhot ~ 500 km/s
independent of 
ULIRGs
Dwarfs
LIRGs
Ram pressure in hot wind
Vterm ~ Vhot ~ 500 km/s
L ~ LEDD 
Vterm ~ 
Data from Martin (2005)
The Maximum Luminosity of Starbursts
Black Holes
• Efficient angular momentum transport in mergers
can trigger BH growth and AGN activity
1/2
• Dust present outside Rsub ~ 1 L1/246 pc
• If L  LM, AGN can blow dusty gas out of
its vicinity, controlling its own fuel supply
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
1/2
• ‘Normal’ optically thin Eddington limit applies
• With sufficient fuel supply, L ~ LEDD  MBH
• As BH grows, L  LM  4
4
L EDD ~ L M when M BH ~ 108 M f 0.1  200

Is the BH or Stellar Feedback
Responsible for the Bulk of the Gas
Removal?
• L*=4fg4c/G seen; implies radiation limited (not BH
limited) star formation rate
• Winds are seen; if massive enough, Faber-Jackson
follows. Not blown by AGN
• BH is affected by  but not fg; fine tuning required to
arrange for Faber-Jackson
• See ongoing star formation in ellipticals (at low level)-no supression of star formation in situ
• But AGN feedback likely restricts mass accretion
from large radii
Feedback in Galactic Disks
•
•
•
•
•
v c vT
1
Marginally Stable: Q 
Gr
H/R~vT/vc roughly constant
Stars form in molecular gas
dN/dM~ M-1.8
=>
mass
in
big
clouds

Most stars form in Giant Molecuar
Clouds
Clumps and Star Clusters
• IRDCs: dN/dM~M-1.97 (Simon et al. ApJ 2006)
• Clumps: dN/dM~M-1.8
• Molecular Cloud Cores dN/dM~-1.7 (Lada,Bally
& Stark 1991)
• Clusters: dN/dM~M-2 (Lada & Lada 2003)
• => Most stars form in massive clusters
Carina
• Mass GMC ~ 5x105 Solar masses
• Radius GMC ~ 40pc
• L=2.5x107 Lsun (~1041 erg/s)
– 70% from Trumpler 16, 16% from Tr 14
– Rcl ~ 2pc
• X-rays consistent with standard IMF
Clumps in Carina
Forces Acting In Carina
• Inward
– Self-Gravity of shell -GMsh(R) Msh(R)/R2
– Turbulent pressure 4r2 vT2
– Ram pressure
4r2 vsh2
• Outward
– HII gas pressure
• 4r2 nkT = 4r2 (3Q/4r3)1/2 kT
– Radiation pressure (1+)L/c,  <1
– Jet ram pressure
dM/dt vjet
Dynamical Model (1D)
Dynamical Model (1D)
Dynamical Model (1D)
Dynamical Model (1D)
Dynamical Model (1D)
Summary
(Local Feedback)
•
•
•
•
•
•
Star formation is observed to be inefficient
Scaling relations imply a single mechanism
SN too late to halt SF in Starbursts/ULIRGS
HII helps in MW, not in ULIRGS
Stellar Winds seem ineffective
Radiation pressure on dust can work