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SSP vs Galaxies

Galaxy: Complex chemistry Age distribution. Differential extinction In space In age. Held et al 04. SSP vs Galaxies. SSP: Chemically Homogeneous Coheval Seldom affected by differential extintion Single IMF. Variable IMF ?. S: stellar birth rate

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SSP vs Galaxies

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  1. Galaxy: • Complex chemistry • Age distribution • Differential extinction • In space • In age Held et al 04 SSP vs Galaxies • SSP: • Chemically Homogeneous • Coheval • Seldom affected by differential • extintion • Single IMF • Variable IMF ?

  2. S: stellar birth rate fl: star(M,t,Z) spectrum Without dust a bare integral ! All difficulties in St. Evol. And St. Atmosph. !! If S=y(t)*f(m)(Bruzual 86) then integrate SSP instead of single stars ! y(t) & Z(t) provided by chemical evolution Chemo-Spectrophotometric Population Synthesis First consistent chemo + stellar evolution + spectral code by Bressan et al 94 Many other synth. tools, e.g. Bruzual & Charlot 90-06…, Jimenez et al 00… etc..

  3. CHEMICAL EVOLUTION OF GALAXIES • A simple model: • Close model (no inflow and/or outflow of gas) • IMF constant in time • Instantaneous mixing of ejected material • Initial gas is primordial Initial conditions

  4. E(t): the rate of gas ejection by dying stars mr is the mass of the remnant tm is the lifetime of the star with mass m EZ(t): the rate of metal ejection by dying stars pZm : mass fraction of newly produced and ejected elements

  5. Instantaneous Recycling Appr. • Stars with mass < mI (=1 MŸ) never day tm = ∞ • Stars with mass ≥ mI have negligible lifetime tm = 0 • R is the mass returned to the ISM by a simple stellar population • R is constant as long as mr does not depend on Z

  6. NOTE: Independent from the mass of the galaxy Other physics needed to interpret Z-Mass relations For Z << 1:

  7. For a more detailed description: • Stellar Evolution: • lifetimes • detailed ejecta (vs. mass & composition, SNIa) • Gas: • mixing processes, inflow & outflow, heating and cooling • Stellar birthrate: • star formation efficiency & IMF • (e.g. revs. by Matteucci 03, Pagel 03)

  8. StellarYields From Portinari et al 98 NS RM Yields computed adopting ejecta (Mo) vs MCOof Woosley &Weaver 95

  9. SN Ia yields Element M/Mo Nomoto et al 84

  10. Observations: Thin & Thick Disk A04 = AllendePrieto et al. (2004) B03 = Bensby et al. (2003) B04a= Bensby et al. (2004)C00 = Chen et al. (2000) E93= Edvardsson et al. (1993)F00 = Fulbright (2000) G03= Gratton et al. (2003)M04 = Mishenina et al. (2004) N97 = Nissen & Schuster (1997)P00 = Prochaska et al.(2000) R03 = Reddy et al. (2003) (from Soubiran & Girard 05)

  11. Linear Trends • For the thin disk : • [Mg/Fe]=-0.37[Fe/H]-0.040 s =0.067 dex • [a/Fe]=-0.29[Fe/H]-0.029 s =0.052 dex • For the thick disk : • [Mg/Fe]=-0.41[Fe/H]+0.097, s =0.092 dex • [a/Fe]=-0.30[Fe/H]+0.071, s =0.069 dex (from Soubiran & Girard 05)

  12. Observations and Chemical Ev. Model for Solar Vicinity Chemo-kinematical parameters for 424 stars Rocha-Pinto et al. 04

  13. Cayrel et al 00 Need some Yield adjustement !!!! corrected

  14. Caffau et al. 06

  15. With detailed SFR & chemistry • Gas fraction and Z • dust fraction • SNIa, Ib/c and II rates • SNIIs allow prediction of radio emission • Detailed abundance of gas going into SF(t) • effects of enhancement in norrow band indices

  16. (Panuzzo et al 06) NGC4435 • NGC4435 is an SB0(7) in interaction with NGC4438 (spiral): nearest passage about 100 Myr ago(Vollmer et al 05) • MBH by Coccato et al 05 • Opt. Pop. Study by Sarzi et al 05 • MIR spectrum typical of a star forming object (spiral NGC7331)

  17. GRASIL FIT OLD MC Diffuse dust NGC 4435 UV+NIR+MIR+FIR + RadioOLD+Starburst

  18. Best fit model of central 5” with GRASIL (Silva et al 98, Vega et al 05) Old M ~ 8 109M⊙ Age ~ 9 Gyr Z = 0.02 Young: post starburstwith residual SFR~0.07 M⊙/yr Age~ 180 Myr <SFR>~0.7 M⊙/yr MBURST~ 1.2 108M⊙~ 1.5% MGAL (5 arcsec) PAH model (Li & Draine 01, Vega et al 05) needs revison above 14 mm

  19. Today more complex models • Multi-phase models (heating, cooling of gas) • Semi-analitic models (Durham, Munich, etc..) • Effects of dust reprocessing (e.g. GRASIL) • Galaxy-AGN co-evolution (e.g. Granato et al 04)

  20. SSP in the MIR 10µm bump:Dusty AGB envelopes ? • O-rich SSP models (Bressan et al 98) • The emission feature is very similar to observed O-rich AGB outfows (ISO, Molster et al. 2000)

  21. Emission Lines 2 galaxies (12%) N4636[NeII]12.8 mm [NeIII]15.5 mm [SIII]18.7 mm N4486[ArII]7 mm [NeII]12.8 mm [NeIII]15.5 mm [SIII]18.7 mm ( M87 )

  22. PAHs 2 Galaxies (12%) N45506.2, 7.7, 8.6, 11.3, 11.9, 12.7mm N44356.2, 7.7, 8.6, 11.3, 11.9, 12.7, 16.4mm also [ArII]7 mm, [NeII]12.8 mm, [NeIII]15.5 mm, H2S(1)17.04 mm [SIII]18.7 mm

  23. Total fluxes Total fluxes Nuclear Fluxes Nuclear Fluxes M87 a young nuclear population?

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