romeel dav with ben oppenheimer kristian finlator dusan keres neal katz david weinberg n.
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Galactic Outflows and Missing Baryons

Galactic Outflows and Missing Baryons

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Galactic Outflows and Missing Baryons

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  1. Romeel Davé with: Ben Oppenheimer, Kristian Finlator, Dusan Keres, Neal Katz, David Weinberg, + Galactic Outflows and Missing Baryons

  2. I met a baryon who wasn’t there... Baldry+08 McGaugh+09

  3. it wasn’t there again today...

  4. I wish, I wish it’d go away. Halo mass function, scaled by Wb/Wm. Quenching UV Photons Outflows Baldry+ 08

  5. Solve overcooling • Enrich the IGM • Establish the mass-metallicity relation • Keep dwarf galaxies faint & gas rich • … Can we a find a model that does all this? What can outflows do for you?

  6. Outflows: Observations & Implications Common at z~1+: ΣSFR>>0.1 M⊙/kpc2 ΔvISM~ hundreds km/s Local SBs, z~1 SFG: vwvcircMomentum-driven winds? If so, mass loading factor η1/vcirc Note: Similar scalings may arise from other physical mechanisms. M82: Spitzer 8μ Martin 2005 100

  7. Outflows in Gadget-2 Kick particles with vw, in vxa direction. Monte Carlo: Proboutflow=ηProbSF vw and η related to Mgal(vcirc).

  8. Outflows enrich the IGM IGM too hot Momentum-driven wind scalings! Too few metals produced Too few metals in IGM wind speed Diffuse IGM unenriched mass loading • z~2-4 CIV absorbers quite constraining; favor momentum-driven wind scalings.

  9. Gas+metal content z=2 Finlator&RD 08 • h1/vcirc keeps smaller galaxies more gas-rich. • Large outflow rates don’t make galaxies gas-poor, but gas-rich. • MZR shape, amplitude, scatter reproduced by h1/vcirc • Other wind models, e.g. h=const, don’t work.

  10. Halo baryon & stellar content

  11. ICM Enrichment + Pre-heating • [Fe/H]~⅓Z, regardless of winds. • No winds: f*~0.3-0.5; winds reduce f* by 2x. • [O/Fe] sensitive to winds: it’s distribution, not production. • Intragroup gas shows excess entropy over no winds: “pre-heating”. • ICM is pre-heated to observed levels naturally with outflows (no AGN). RD+ 08

  12. Constant winds Mom-driven winds No winds no winds, 8e-5 constant winds, 0.037 MD winds, 0.51 DLA Kinematics: Outflows? • Wide separation (v>vrot) DLAs hard to produce; protogalactic clump infall fails (eg Pontzen etal). S. Hong, Katz, RD etal, in prep Prochaska & Wolfe 01 KS test prob

  13. Wind mass & recycling % of Baryons Total wind baryons: ~20%

  14. Summary: Outflow Intuition Galactic outflows… Drive substantially more mass out than forms into stars–star formation is a perturbation! Drive mass to well beyond the virial radius–to enrich IGM and suppress halo baryon fraction. Drive (proportionally) more mass out of smaller galaxies–but not because of smaller potential. Exhibit differential recycling–so that small galaxies are more suppressed to late times. Momentum-driven scalings work well, and as a bonus are like locally observed winds. Missing halo baryons provide critical test.

  15. Wind mass & energy • Mass loading factor typically > 1 • Globally, many times more mass in outflow than forms into stars! • Energy comparable to SN energy

  16. Feedback Tomography • Background sources observe outflows in action. • Tough now, but will become routine at z~2+ in 30m era. • COS enables at z<1 • Also possible in emission around galaxies. • The next frontier of observational galaxy formation!

  17. What can outflows do for YOU?

  18. z=2 Finlator&RD 08 Mass-Metallicity Relation • Conventional thinking: • Zgas reflects stage of processing • Galaxies lose metals based on F. • NO! Why? Outflows are greedy & destructive: • They don’t share their energy -- they blow holes! Z~M1/3 Analytic 3D simulation

  19. z=2 Finlator&RD 08 The “Equilibrium” MZR Model   • Z ~ y M*/Macc ~ y (1+h)-1 • For mom-driven winds: h~M*-1/3~vc-1Z(M*)~M*1/3 • Zgas set by an equilibrium between recent inflow and outflows. • Tightness of MZR set by timescale to return to equilibrium. Z~M1/3