1. Chemical Evolution in the Universe (and galaxies) Romeel Davé Kristian Finlator Ben D. Oppenheimer University of Arizona

2. Metals in the Universe  Most metals are not in galaxies (Pettini 99), but rather the IGM.  IGM tells us: Metals must be transported over large (~Mpc) scales, starting early on.  Outflows establish the balance of metals in various cosmic baryon phases.  … or in reverse, observations of metals in various phases can constrain outflows.  Idea: Use cosmological simulations + observations to constrain outflow properties and understand chemical enrichment.

3. Outflows typical at high-z   Common at z~1+:   Σ SFR >>0.1 M ⊙ /kpc 2   Δv ISM ~ hundreds km/s   Local SBs, z~1 SFG: v w  v circ Momentum-driven winds?   If so, outflow rate η  1/v circ where  = M outflow /M *.   How do outflows impact IGM & galaxies? Use metals as tracers. M82: Spitzer 8 μ Martin 2005 100

4. Outflows in Gadget-2   Kick particles with v w, in vxa direction.   Monte Carlo: Prob outflow =ηProb SF   v w and η related to M gal (   ) and SFR.   For mom-driven winds (OD08): Recycling time ~1 Gyr, distance~100 physical kpc http://luca.as.arizona.edu/~oppen/IGM/

5. Chemical Enrichment  Track 4 metals: C, O, Si, Fe.  3 sources: Type II + Ia SN, AGB stars.  AGB stars return mass+Z into ISM.  Star-forming gas is continually self- enriched. When ejected, it carries metals into IGM. No diffusion.  Primary constraint: IGM enrichment.  Winds are only way to get metals out that far, that early!

6. IGM enrichment  Goldilocks & 3 winds:  Momentum-driven scalings  Weak (E<E SN )  Constant (v w ~500km/s,η=2) wind speed mass loading Too few metals in IGM IGM too hot Diffuse IGM unenriched Too few metals produced Momentum-driven wind scalings! ~ log δ Oppenheimer & RD 2006

7. Luminosity functions  z~6 UVLF: large SF suppression.  Rapid consumption  must eject gas.  M acc = M * +M outflow  SFR  (1+  ) -1  z~2-4 LF:  Const    ~2+   ~ v c -1   ~1.7  z=0: Faint end slope of  (M * ) not too bad! (bright end?… ugly) Data: Bouwens etel 06 Models:  =0.3,  8 =0.9 RD, Finlator, Oppenheimer 06 

8. Mass-Metallicity Relation  Observed: Z gas  M * 0.3 from M * ~10 6  10 10.5 M , then flattens. Low scatter,  ≈0.1.  Conventional thinking: –Z gas reflects current stage of gas reservoir processing. –Winds carry metals more easily out of small galaxies. WRONG !!! (at least according to our simulations) Tremonti etal 04 Lee etal 06

9. Z~M 1/3 MZR: Clues from Sims vs. Data z=2 Finlator&RD 08  v wind =const,  =const fails.  v wind ~v esc,  ~1/v esc works!  Why?  Because outflows are greedy & destructive:  They don’t share their energy  They blow holes Analytic3D simulation

10. Z~M 1/3 The Equilibrium Model z=2 Finlator&RD 08  Z ~ y M * /M acc ~ y (1+  ) -1  If v w >v esc, constant   constant Z. For v w v esc, constant   constant Z. For v w <v esc,   0, Z  y. Produces a feature in MZR-- not seen.  For mom-driven winds:  ~M * -1/3 ~v c -1  Z(M * )~M * 1/3  Z gas set by an equilibrium between recent inflow and outflows. 

11. MZR Evolution  M * -Z relation is predicted to have slow evolution from z=4  0 (0.05 dex/z).  Only note slope, evolution, & scatter; amplitude ±0.3+.  Galaxies enrich early!   Turnover at hi-M due to  <1 at large , not potential well (recall Z~y/(1+  ),  1/  ) RD, Finlator, Oppenheimer 06

12. MZR Scatter  Lee etal 06 noted that standard scenario over- produces scatter at low M*.  In our model, scatter comes from departures from Z eq from stochastic accretion/merging.  Timescale to return to Z eq : t d =M gas /M acc (dilution time).  Small t d  low scatter.  MD winds have t d <t dyn at all epochs & masses. Finlator & RD 07 

13. Baryon fractions  Winds keep galaxies gas-rich.  …but only if mass loading is large in small galaxies!  Galaxies lose sub- stantial mass early.  MW sized halo at z=0 has half its “share” of baryons. z=0 z=2

14.  L X -weighted [Fe/H]  ~1/3 Z , as observed.  No winds looks ok, but stellar baryon fraction >> observed; spurious!   Need outflows to spread baryons in ICM.  Intragroup gas shows excess entropy over no winds; “pre-heating”.  ICM is pre-heated to correct levels naturally with outflows. RD etal in prep ICM Enrichment & Pre-heating

15. Summary   Star formation and enrichment in galaxies strongly regulated by outflows.   Generally, need more mass loss from smaller galaxies.   Momentum-driven scalings work well:   Mass-metallicity relation slope & scatter.   IGM enrichment (CIV @z~2-4, OVI at z~0)   Keeps small galaxies gas-rich, with less stars.   Bonus: Consistent with observed winds.   Mass-metallicity relation set by equilibrium between recent inflows and outflows, governed by outflow rate not potential wells.

16. Discussion Topics  Best direct way to constrain outflows?  ISM absorption: Velocity info but not dM/dt.  X-ray emission: Energy info, but little else.  Best indirect way to constrain outflows?  IGM absorption (feedback tomography)  Mass-metallicity relation  Stellar mass evolution (i.e. SF efficiency)  Does [  /Fe] tell us anything about outflows?  How can MW studies of accretion/SF help?  Is a closed box model OK for passive gals?  Where do AGB products (e.g. C) end up?

17. Reionization Epoch  Galaxy formation different?  Radiative feedback  Non-equilibrium ionization  Mini-halo contribution?  Top-heavy/Pop III IMF?  Mini-quasars?  Basic questions:  Topology: Outside-in, inside-out, or ???  Enough photons from “normal” IMF?

18. Typical SF Histories: Rapid, Early Assembly  Gadget simulations vs. z>5.5 galaxies w/IRAC data.  In most cases, simul- ated galaxies provide good fit (  2 <1).  Best-fit galaxies…  are fairly massive,  have older stars,  show 4000Å break.  Typical SFH is constantly rising. Finlator, RD, Oppenheimer 06 log M * =8.7 log M * =10.1 log M * =9.2 log M * =10.1 log M * =9.4 log M * =9.3

19. 2 Let's do it right: Rad Hydro  Moment-based scheme (like OTVET, without the “OT”, i.e. optically thin assumption).  Use long characteristics to compute Eddington tension and close moment hierarchy.  For now, post-process hydro outputs.  SFH  Spectrum (BC03)  Working on combining w/Gadget. 1 3 Finlator, Ozel, RD 08

20.  If we suppress SF, does that hamper ability to reionize?  Even w/10% escape fraction, plenty of photons!  Key: Clumping factor much lower than often assumed (30).  Clumping factor evolves strongly! Fan+06 Gnedin & Ostriker (1997) Pawlik & Schaye (2008); Bolton & Haehnelt (2008) Enough photons to reionize? Finlator et al 08, in prep

21. Topology Evolution?  Outside-in? Miralda-Escude et al 00  Inside-out? Simulations; eg Iliev etal 06  Our result: Inside  outside  middle! (see also Choudhury etal) http://norno.as.arizona.edu/~kfinlator/rt/index.html

22. Early Galaxy Formation  Galaxies & IGM connected via outflows.  Outflow rate >~ star formation rate  Accretion ≃ SFR + Outflow rate  Early star formation: It's NEVER too big for CDM (almost).  Mass-metallicity relation from outflows: Not what you think.  Are there enough photons to reionize the Universe by z=9?

23. DLA Kinematics: Outflows?  Wide separation (  v>v rot ) DLAs hard to produce; protogalactic clump infall fails (Pontzen etal).  Momentum-drive winds puff out gas, produces wide-separation systems. Prochaska & Wolfe 01 KS test prob no winds, 8e-5 constant winds, 0.037 MD winds, 0.51 No winds Mom-driven windsConstant winds S. Hong, Katz, RD etal, in prep

24. Constant  CIV ≠ Early IGM Enrichment   CIV ~constant (z=2-5.5).  Simple model: Pop III stars inject metals at z>6.  WRONG.  Successful wind models show  CIV ~constant, but  CIV increasing by x10.  Early injection yields  CIV increasing  CIV !  Hence constant  CIV supports in situ enrichment. Oppenheimer & RD 06

25. Missing metals  Pettini 99: Metals in z~3 galaxies << Metals produced by stars.  Strong outflows?  Simulations: 40% of metals in diffuse IGM @ z=3; only 10% in stars, 10% in cold gas.  Shocked IGM (WHIM) has ~20% at all z.  But is it only metals ejected, or mass? RD & Oppenheimer 07