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Stellar & AGN Feedback in Galaxies GLCW8 Columbus 2007.

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Presentation on theme: "Stellar & AGN Feedback in Galaxies GLCW8 Columbus 2007."— Presentation transcript:

1 Stellar & AGN Feedback in Galaxies GLCW8 Columbus 2007

2 Evidence for Feedback (Self-limited Star Formation?) M b ~ 3 M * ~ 4 Krabbe et al astro-ph/

3 Inefficient Star Formation-Feedback? Kennicutt 1998 Implies same physics over 4 decades in gas

4 Evidence for Feedback: Winds- significant mass & momentum in cold gas M82 (Subaru) e.g., Heckman et al. 00; Martin 04,05

5 Evidence for Feedback (self-limiting BH accretion?) Greene & Ho 05

6 Large-Scale Feedback Fabian et al (2006) Perseus Cluster

7 Fabian et al (2006) Perseus Cluster Large-Scale Feedback

8 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

9 Radiation Pressure Feedback Dust absorbs the radiation produced by starbursts or AGN Dust collisionally coupled to the gas: mfp ~ 1 a 0.1 n 1 pc Starlight provides turbulent pressure support of ISM Momentum-driven wind: V ~ V c L/c M W V L ~ M * c 2 ~ M W V c M W ~ 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) · ····

10 Terminal Velocity of Outflowing Cold Gas Data from Martin (2005) V term ~ 2.5 ~ V esc ULIRGs LIRGs Dwarfs Hot gas inferred to have V hot ~ 500 km/s independent of Ram pressure in hot wind V term ~ V hot ~ 500 km/s L ~ L EDD V term ~

11 The Maximum Luminosity of Starbursts

12 Black Holes Efficient angular momentum transport in mergers can trigger BH growth and AGN activity Dust present outside R sub ~ 1 L 1/2 46 pc If L L M, AGN can blow dusty gas out of its vicinity, controlling its own fuel supply 1/2

13 The Maximum Luminosity of Quasars from width of OIII line in NLR

14 The Origin of the M- Relation? Inside R sub ~ 1 L 46 pc, dust destroyed Normal optically thin Eddington limit applies With sufficient fuel supply, L ~ L EDD M BH As BH grows, L L M 4 1/2

15 Is the BH or Stellar Feedback Responsible for the Bulk of the Gas Removal? L * =4f g 4 c/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 f g ; 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

16 Feedback in Galactic Disks Marginally Stable: H/R~v T /v c roughly constant Stars form in molecular gas dN/dM~ M -1.8 => mass in big clouds Most stars form in Giant Molecuar Clouds

17 Clumps and Star Clusters IRDCs: dN/dM~M (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

18 Carina Mass GMC ~ 5x10 5 Solar masses Radius GMC ~ 40pc L=2.5x10 7 L sun (~10 41 erg/s) –70% from Trumpler 16, 16% from Tr 14 –R cl ~ 2pc X-rays consistent with standard IMF

19 Clumps in Carina

20 Forces Acting In Carina Inward –Self-Gravity of shell -GM sh (R) M sh (R)/R 2 –Turbulent pressure 4 r 2 v T 2 –Ram pressure 4 r 2 v sh 2 Outward –HII gas pressure 4 r 2 nkT = 4 r 2 (3Q/4 r 3 ) 1/2 kT –Radiation pressure (1+ )L/c, <1 –Jet ram pressure dM/dt v jet

21 Dynamical Model (1D)





26 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

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