Stellar & AGN Feedback in Galaxies

GLCW8 Columbus 2007

Evidence for Feedback(Self-limited Star Formation?)

Mb~3

M*~4

Krabbe et al

astro-ph/0703804

Inefficient Star Formation-Feedback?

Kennicutt 1998

Ý *; 0.017

Implies same physics over 4 decades in gas

Evidence for Feedback: Winds-significant mass & momentum in cold gas

M82 (Subaru)

e.g., Heckman et al. 00; Martin 04,05

Evidence for Feedback(self-limiting BH accretion?)

Greene & Ho 05

Large-Scale Feedback

Fabian et al (2006)

Perseus Cluster

Fabian et al (2006)

Perseus Cluster

Large-Scale Feedback

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)

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· · · ·

Terminal Velocity of Outflowing Cold Gas

Data from Martin (2005)

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 ~

The Maximum Luminosity of Starbursts

Black Holes• Efficient angular momentum transport in mergers

can trigger BH growth and AGN activity

• 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

1/2

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

LEDD ~ LM when MBH ~ 108M f0.1 2004

Is the BH or Stellar Feedback Responsible for the Bulk of the Gas

Removal?

• L*=4fg4c/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

• Marginally Stable:

• 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

Qvc vTGr

1

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 4r2 vT2

– Ram pressure 4r2 vsh2

• Outward– HII gas pressure

• 4r2 nkT = 4r2 (3Q/4r3)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