Sally Oey University of Michigan Cathie Clarke IoA, Cambridge HDF Smith et al. / MCELS Massive Stars: Feedback Effects in the Local Universe

Massive Star Feedback  Radiative  Mechanical  Chemical Smith et al. / MCELS > 8 M o 3 – 40 Myr lifetimes

THE MASSIVE STAR POPULATION  N * : Clustering law, field  m : Stellar IMF Distributions: NGC 346 Nota et al. 2006

The IMF Upper-mass cutoff IC Berkeley 8610 NGC NGC NGC Tr 14 / 1682 LH 1065 LH 117 / Total 263 R136a / 30 Dor > 650 Grand Total > 913 Massey et al Massey & Hunter 1998, Hunter et al Observed OB associations ages 10 M o Arches: Figer 2002, 2005 R136a: Weidner & Kroupa 2004, Oey & Clarke 2005

m max expectation value N*N* Oey & Clarke (2005) OB + 30 Dor OB’s implies m up < 200 M o cf. Elmegreen (2000): Milky Way m up ~10,000 M o

P < P < 0.12 P < 0.02 P < 0.47 Probabilities for massuming m up Probabilities for m max assuming m up m up ~ 150 M m up ~ 150 M  Oey & Clarke 2005 see also Koen (2006) Entire sample

A Universal Clustering Law Starbursts Meurer et al Globulars and Massive young Clusters Elmegreen & Efremov 1997, Hunter et al / / Antennae Zhang & Fall 1999 HST / B. Whitmore

a Universal Clustering Law and a Universal IMF ? A steep field IMF a steepening N * A steep field IMF a steepening N * (fewer massive) (more low-N * ) (fewer massive) (more low-N * ) Massey (1995, 2002); Kroupa & Weidner (2003) All / No field / Oey, King, & Parker 2004 SMC Field stars fall on clustering law

Fraction of Field Massive Stars: 35% to 7% for N *,up = 10 to 10 6 SMC: expect ~20%, see ~26% modest dependence on total SFR Oey, King, & Parker 2004

RADIATIVE FEEDBACK Nebular emission H [S II], [O III], V, R Large Magellanic Cloud MCELS Smith et al  HII Region LF  Diffuse, warm ionized medium

1.Break in slope 2.Arm populations: shallower a Interarm populations: steeper a 3.Hubble Type correlation a ~ 1.7 Sc – Im a ~ 2.0 Sb – Sc a ~ 2.6 Sa a ~ 1.7 Sc – Im a ~ 2.0 Sb – Sc a ~ 2.6 Sa log N(L) log L HII Region Luminosity Function a Universal Clustering Law and a Universal IMF ? Oey & Clarke 1998

Ionization of the Diffuse WIM Field stars: ~ 50% WIM ionized by field ~ 50% WIM ionized by field Oey et al. 2004; Hoopes & Walterbos 2000 Leaky nebulae: LMC: up to 50% ionizing photons escape LMC: up to 50% ionizing photons escape Oey & Kennicutt 1997; Gerken, Walterbos, & Oey 2003 Ha Milky Way WHAM: Reynolds et al.

MECHANICAL FEEDBACK DEM L152 R. C. Smith & MCELS Small Magellanic Cloud Staveley-Smith et al H I H [S II], [O III] ~100 pc diameter

Superbubble size distribution + + Oey & Clarke 1997 Global Mechanical Feedback = clustering law

prediction observed Oey & Clarke 1997 Velocity distribution Oey & Clarke 1998 Predicted -3.5 Observed /- 1.4 Predicted /- 0.4 Observed /- 0.6 Size distribution

Ionizing photons escape into ISM?...into IGM? Reionization of Universe? Escape of hot gas, stellar products and ionizing photons?

Clarke & Oey 2003 The first galaxies: ? MW: LBGs: Starbursts: Ambiguous porosity e.g., Oey & Clarke 1997 Lyman cont seen? Steidel et al Critical SF Threshold Lyman cont seen in Haro 11 Bergvall et al. 2006

ESO 300-G14 NGC 7713 H a R-band SINGG: Survey of Ionization in Neutral Gas Galaxies H  survey of HIPASS galaxies Meurer et al. (2006) Oey et al. (2006, in prep) IC 5052

High SF intensity : Less WIM

Possible causes for high SFI : less WIM  Ionization source reduced: – Output from HII regions reduced – Fewer field OB stars  Starbursts occupy ISM and Remaining WIM density-bounded Ionizing photons escape

Fraction of Field Massive Stars: 35% to 7% for N *,up = 10 to 10 6 SMC: expect ~20%, see ~26% modest dependence on total SFR Oey, King, & Parker 2004 recall

Diffuse fraction vs. total SFR

Clarke & Oey 2003 MW: LBGs: Starbursts: Ambiguous porosity e.g., Oey & Clarke 1997 Lyman cont seen e.g., Steidel et al Critical SF Threshold J recall

Trend for HI-poor galaxies

 Ionization source reduced: – Output from HII regions reduced – Fewer field OB stars  Starbursts occupy ISM and Remaining WIM density-bounded Ionizing photons escape Likely ? Possible causes for high SFI : less WIM LyC seen from Haro 11 Bergvall et al. 2006

CHEMICAL FEEDBACK Q: filling factor n: generations Inhomogeneous evolution Stochastic Inhomogeneous evolution Oey 2000, 2003

data: Carney et al. (1996) Simple: Halo is evolved SIM: Halo is unevolved (Oey 2003) Thick disk MDF Thin disk MDF Thick disk MDF Bensby & Oey (2006), in prep data: Nordstrom et al. (2004) selection: Bensby et al. (2003, 2005) Halo MDF

Zero-metallicity (Pop III) stars (Oey 2003) For Galactic halo model For Galactic halo model F III ~ 4e-2 vs. Observed F III < 4e-4 Clear discrepancy!

OB clustering H II LF, WIM Superbubbles Field fraction: ionizing WIM, IGM relation to IMF ISM structure, evolution m up ~ 150 M o Massive Star Feedback

Superwind threshold Metal enrichment Simple Inhomogeneous Model GCE of unevolved systems A self-consistent analytic approach starburst feedback to IGM

Massive Star Feedback  OB population: clustering law, IMF  Radiative: HII LF, diffuse 10 4 K gas  Mechanical: superbubbles, superwinds diffuse 10 6 – 10 7 K gas  Chemical: inhomogeneous chemical evolution

Adiabatic shell evolution L = mech luminosity n = ambient density t = age

– ~ 1 M31 M33 LMC SMC IC 10 LG dwarfs Milky Way (HII LF) Milky Way (SN rate) QGalaxy Porosity: Hot, ionized medium Oey & Clarke 1997, Oey et al volume filling factor of hot ISM superwind mass-loss rate Mac Low & McCray (1988) clustering  = 2

Starbursts ( Clarke & Oey 2002 ) DistributedvsNuclear Equal contrib to porosity by all superbubble R Oey & Clarke 1997 He 2-10: He 2-10: Chandar et al Field population = SSC’s Field population = SSC’s LF L -2 LF L -2 Field OB’s formed in situ Field OB’s formed in situ

R136a / 30 Dor Consistent with no m up Massey & Hunter 1998; Massey 2003 Suggests m up ~ 150 M o Selman et al Consistent with Salpeter slope Expect (14, 19) Expect (14, 19) having m > 120 M o Found (2, 9) stars Found (2, 9) stars If no m up : 1.7x N * ( 85 – 120 M o ) Massey & Hunter 1998 (See also Weidner & Kroupa 2004)

Monte Carlo model Oey & Clarke 1998 zero-age evolved

CHEMICAL FEEDBACK Nucleosynthesis Nucleosynthesis Chemical evolution Chemical evolution MIXING : local MIXING : local HOMOGENIZATION : global HOMOGENIZATION : global IN/OUT-FLOW : open box IN/OUT-FLOW : open box

Simple Inhomogeneous Model Q: filling factor = const n: generations (Oey 2000, 2003) Early times: Stochastic Inhomogeneous evolution

Multi-generation Parent metallicity distribution function

Inhomogeneous evolution: Dispersion Argast et al. (2000) [Fe/H] Audouze & Silk (1995) Thin disk: Oey & Bensby

McWilliam (1997) Cayrel et al. (2005)

mtl-rich + old: high Q e.g., Bulge mtl-rich + old: high Q e.g., Bulge mtl-poor + old: low Q e.g., I Zw 18 mtl-poor + old: low Q e.g., I Zw 18 n = 4 Q = 0.72 n = 24 Q = 0.72 n = 24 Q = 0.12 Evolution parameter: nQ  = nQ  2 = nQ(1-Q)