Chemical Evolution in Chemical Evolution in the Universe the Universe (and (and galaxies)galaxies)

Romeel DavéRomeel DavéKristian FinlatorKristian Finlator

Ben D. OppenheimerBen D. OppenheimerUniversity of ArizonaUniversity of Arizona

Metals in the UniverseMetals in the Universe Most metals are not in galaxies (Pettini 99), but Most metals are not in galaxies (Pettini 99), but

rather the IGM.rather the IGM. IGM tells us: Metals must be transported over IGM tells us: Metals must be transported over

large (~Mpc) scales, starting early on.large (~Mpc) scales, starting early on. Outflows establish the balance of metals in Outflows establish the balance of metals in

various cosmic baryon phases.various cosmic baryon phases. … … or in reverse, observations of metals in or in reverse, observations of metals in

various phases can constrain outflows.various phases can constrain outflows.

IdeaIdea: Use cosmological simulations + : Use cosmological simulations + observations to constrain outflow properties and observations to constrain outflow properties and understand chemical enrichment.understand chemical enrichment.

Outflows typical at high-zOutflows typical at high-z Common at z~1+:

ΣSFR

>>0.1 M⊙/kpc2

ΔvISM

~ hundreds km/s Local SBs, z~1 SFG:

vwvcirc Momentum-driven winds?

If so, outflow rate η1/vcirc

where = Moutflow/M*. How do outflows impact IGM &

galaxies? Use metals as tracers.

M82: Spitzer 8μ

Martin 2005

100

Outflows in Gadget-2Outflows in Gadget-2 Kick particles with v

w, in vxa direction.

Monte Carlo: Proboutflow

=ηProbSF

vw and η related to Mgal() and SFR.

For mom-driven winds (OD08): Recycling time ~1 Gyr, distance~100 physical kpc

http://luca.as.arizona.edu/~oppen/IGM/

QuickTime™ and a decompressor

are needed to see this picture.

Chemical EnrichmentChemical Enrichment Track 4 metals: Track 4 metals: C, O, Si, FeC, O, Si, Fe.. 3 sources: Type II + Ia SN, AGB stars.3 sources: Type II + Ia SN, AGB stars. AGB stars return mass+Z into ISM.AGB stars return mass+Z into ISM. Star-forming gas is continually self-Star-forming gas is continually self-

enriched. When ejected, it carries metals enriched. When ejected, it carries metals into IGM. No diffusion.into IGM. No diffusion.

Primary constraint: IGM enrichment.Primary constraint: IGM enrichment. Winds are only way to get metals out Winds are only way to get metals out

that far, that early!that far, that early!

IGM enrichmentIGM enrichment Goldilocks & 3 winds:

Momentum-driven scalings Weak (E<E

SN)

Constant (vw~500km/s,η=2)

win

d sp

eed

mass loading

Too fewmetals in IGM

IGM too hot

Diffuse IGM unenriched

Too fewmetalsproduced

Momentum-driven wind scalings!

~ log δ

Oppenheimer& RD 2006

Luminosity functionsLuminosity functions z~6 UVLF: large SF z~6 UVLF: large SF

suppression.suppression. Rapid consumption Rapid consumption

must must eject eject gas.gas. MMaccacc = M = M**+M+Moutflowoutflow

SFRSFR (1+ (1+))-1-1

z~2-4 LF:z~2-4 LF: Const Const ~2+~2+ ~ v~ vcc

-1-1 ~1.7~1.7 z=0: Faint end slope z=0: Faint end slope

of of (M(M**) not too bad! ) not too bad! (bright end?(bright end?…… ugly) ugly)

Data: Bouwens etel 06Models: =0.3, 8=0.9

RD, Finlator, Oppenheimer 06

Mass-Metallicity Mass-Metallicity Relation Relation

Observed: ZgasM*0.3 from

M*~1061010.5M, then flattens. Low scatter, ≈0.1.

Conventional thinking:

– Zgas 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

Z~M1/3

MZR: Clues from MZR: Clues from Sims vs. DataSims vs. Data

z=2

Finlator&RD 08

vvwindwind=const, =const, =const fails. =const fails. vvwindwind~v~vescesc , , ~1/v~1/vescesc works! works! Why?Why? Because outflows are Because outflows are

greedy & destructive:greedy & destructive: They don’t share their energyThey don’t share their energy They blow holesThey blow holes

Analytic 3D simulation

Z~M1/3

The Equilibrium The Equilibrium ModelModel

z=2

Finlator&RD 08

Z ~ y MZ ~ y M**/M/Maccacc ~ ~ y (1+y (1+))-1-1

If vIf vww>v>vescesc, constant , constant constant Z. For vconstant Z. For vww<v<vescesc, , 0, Z0, Zy. Produces a y. Produces a feature in MZR-- not seen.feature in MZR-- not seen.

For mom-driven winds:For mom-driven winds:

~M~M**-1/3-1/3~v~vcc

-1-1 Z(MZ(M**)~M)~M**1/31/3

ZZgasgas set by an set by an equilibrium equilibrium between between recent recent inflow and inflow and outflows.outflows.

MZR EvolutionMZR EvolutionM*-Z relation is predicted

to have slow evolution from z=40 (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

MZR ScatterMZR ScatterLee etal 06 noted that

standard scenario over-produces scatter at low M*.

In our model, scatter comes from departures from Zeq from stochastic accretion/merging.

Timescale to return to Zeq: td=Mgas/Macc (dilution time).

Small td low scatter.

MD winds have td<tdyn at all epochs & masses.

Finlator & RD 07

Baryon fractionsBaryon fractions Winds keep galaxies Winds keep galaxies

gas-rich.gas-rich. ……but only if mass but only if mass

loading is large in loading is large in small galaxies!small galaxies!

Galaxies lose sub-Galaxies lose sub-stantial mass early.stantial mass early.

MW sized halo at MW sized halo at z=0 has half its z=0 has half its “share” of baryons.“share” of baryons.

z=0z=2

LX-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-heatingICM Enrichment & Pre-heating

SummarySummary 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.

Discussion TopicsDiscussion Topics Best direct way to constrain outflows?Best direct way to constrain outflows?

ISM absorption: Velocity info but not dM/dt.ISM absorption: Velocity info but not dM/dt. X-ray emission: Energy info, but little else.X-ray emission: Energy info, but little else.

Best indirect way to constrain outflows?Best indirect way to constrain outflows? IGM absorption (feedback tomography)IGM absorption (feedback tomography) Mass-metallicity relationMass-metallicity relation Stellar mass evolution (i.e. SF efficiency)Stellar mass evolution (i.e. SF efficiency)

Does [Does [/Fe] tell us anything about outflows?/Fe] tell us anything about outflows? How can MW studies of accretion/SF help?How can MW studies of accretion/SF help? Is a closed box model OK for passive gals?Is a closed box model OK for passive gals? Where do AGB products (e.g. C) end up?Where do AGB products (e.g. C) end up?

Reionization EpochReionization Epoch Galaxy formation different?Galaxy formation different?

Radiative feedbackRadiative feedback Non-equilibrium ionizationNon-equilibrium ionization Mini-halo contribution?Mini-halo contribution? Top-heavy/Pop III IMF?Top-heavy/Pop III IMF? Mini-quasars?Mini-quasars?

Basic questions:Basic questions: Topology: Outside-in, inside-out, or ???Topology: Outside-in, inside-out, or ??? Enough photons from “normal” IMF?Enough photons from “normal” IMF?

Typical SF Histories: Rapid, Typical SF Histories: Rapid, Early AssemblyEarly Assembly Gadget simulations Gadget simulations

vs. vs. z>5.5 galaxiesz>5.5 galaxies w/IRAC data.w/IRAC data.

In most cases, simul-In most cases, simul-ated galaxies provide ated galaxies provide good fit (good fit (

22<1).<1). Best-fit galaxies…Best-fit galaxies…

are fairly are fairly massivemassive, , have have older starsolder stars, , show show 4000Å break4000Å break..

Typical SFH is Typical SFH is constantly rising.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

2

Let's do it right: Rad HydroLet's do it right: Rad Hydro Moment-based scheme Moment-based scheme

(like OTVET, without the (like OTVET, without the “OT”, i.e. optically thin “OT”, i.e. optically thin assumption).assumption).

Use long characteristics Use long characteristics to compute Eddington to compute Eddington tension and close tension and close moment hierarchy.moment hierarchy.

For now, post-process For now, post-process hydro outputs. hydro outputs.

SFHSFHSpectrum (BC03)Spectrum (BC03) Working on combining Working on combining

w/Gadget.w/Gadget.

1

3Finlator, Ozel, RD 08

If we suppress SF, does If we suppress SF, does that hamper ability to that hamper ability to reionize?reionize?

Even w/10% escape Even w/10% escape fraction, plenty of fraction, plenty of photons!photons!

Key: Clumping factor Key: Clumping factor much lower than often much lower than often assumed (30).assumed (30).

Clumping factor evolves Clumping factor evolves strongly!strongly!

Fan+06Gnedin & Ostriker (1997)

Pawlik & Schaye (2008);Bolton & Haehnelt (2008)

Enough photons Enough photons to reionize?to reionize?

Finlator et al 08, in prep

Topology Evolution?Topology Evolution? Outside-in? Miralda-Escude et al 00Outside-in? Miralda-Escude et al 00 Inside-out? Simulations; eg Iliev etal 06Inside-out? Simulations; eg Iliev etal 06 Our result: InsideOur result: Insideoutsideoutsidemiddle! (see middle! (see

also Choudhury etal)also Choudhury etal)

http://norno.as.arizona.edu/~kfinlator/rt/index.html

Early Galaxy FormationEarly Galaxy Formation

Galaxies & IGM connected via outflows.Galaxies & IGM connected via outflows. Outflow rate >~ star formation rateOutflow rate >~ star formation rate Accretion Accretion ≃≃ SFR + Outflow rate SFR + Outflow rate Early star formation: It's NEVER too big Early star formation: It's NEVER too big

for CDM (almost).for CDM (almost). Mass-metallicity relation from outflows: Mass-metallicity relation from outflows:

Not what you think.Not what you think. Are there enough photons to reionize Are there enough photons to reionize

the Universe by z=9?the Universe by z=9?

DLA Kinematics: Outflows?DLA Kinematics: Outflows? Wide separation (Wide separation (v>vv>vrotrot) DLAs ) DLAs hard to hard to

produce; protogalactic clump infall fails produce; protogalactic clump infall fails (Pontzen etal).(Pontzen etal).

Momentum-drive winds puff out gas, produces Momentum-drive winds puff out gas, produces wide-separation systems.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

Constant Constant CIVCIV ≠ ≠ Early IGM EnrichmentEarly IGM Enrichment CIVCIV~constant ~constant (z=2-5.5).(z=2-5.5). Simple model: Pop III Simple model: Pop III

stars inject metals at z>6.stars inject metals at z>6. WRONG.WRONG. Successful wind models Successful wind models

show show CIVCIV~constant, but ~constant, but CIVCIV increasing by x10. increasing by x10.

Early injection yields Early injection yields CIV CIV

increasingincreasing CIVCIV!! Hence Hence constant constant CIVCIV

supportssupports in situ in situ enrichment.enrichment.

Oppenheimer & RD 06

Missing metalsMissing metals Pettini 99: Metals in z~3 Pettini 99: Metals in z~3

galaxies << Metals galaxies << Metals produced by stars.produced by stars.

Strong outflows?Strong outflows? Simulations: 40% of Simulations: 40% of

metals in diffuse IGM @ metals in diffuse IGM @ z=3; only z=3; only 10% in stars, 10% in stars, 10% in cold gas.10% in cold gas.

Shocked IGM (WHIM) Shocked IGM (WHIM) has ~20% at all z.has ~20% at all z.

But is it only But is it only metalsmetals ejected, or ejected, or mass?mass?

RD & Oppenheimer 07