SSP vs Galaxies

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SSP vs Galaxies

• SSP
• Chemically Homogeneous
• Coheval
• Seldom affected by differential
• extintion
• Single IMF

• Variable IMF ?

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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..
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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
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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
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Instantaneous Recycling Appr.

• Stars with mass lt mI (1 MŸ) never day tm 8
• 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

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For Z ltlt 1
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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)

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Stellar Lifetimes
Bressan 94
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Stellar Yields
Remnant mass and ejecta (Mo) vs MCO (Woosley
Weaver95) Circles ZZo squares Z0.1 Zo
triangles Z0.01 Zo
From Portinari et al 98
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Stellar Yields
From Portinari et al 98
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StellarYields
From Portinari et al 98
NS
RM
Yields computed adopting ejecta (Mo) vs MCO of
Woosley Weaver 95
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SN Ia yields
Element M/Mo
Nomoto et al 84
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Observations Thin Thick Disk
A04 Allende Prieto 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)
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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 -0.41Fe/H0.097, s 0.092 dex
• a/Fe -0.30Fe/H0.071, s 0.069 dex

(from Soubiran Girard 05)
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Observations and Chemical Ev. Model for Solar
Vicinity
Chemo-kinematical parameters for 424 stars
Rocha-Pinto et al. 04
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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

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NGC 4435
(Panuzzo et al 06)

• NGC 4435 is an SB0(7) in interaction with NGC
  4438 (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 NGC 7331)

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UVNIRMIRFIR RadioOLD Starburst
NGC 4435
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Best fit model of central 5 with GRASIL
(Silva et al 98, Vega et al 05)
Old M 8 109 M? Age 9 Gyr Z 0.02
Young
post starburst with residual SFR 0.07
M?/yr Age 180 Myr ltSFRgt 0.7
M?/yr MBURST 1.2 108 M? 1.5 MGAL (5
arcsec)
PAH model (Li Draine 01, Vega et al 05) needs
revison above 14 mm
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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)

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SSP in the MIR 10µm bumpDusty 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)

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Emission Lines 2 galaxies (12)

N4636 NeII12.8 mm
NeIII15.5 mm SIII18.7 mm N4486 ArII7 mm
NeII12.8 mm NeIII15.5 mm SIII18.7 mm
( M87 )
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PAHs 2 Galaxies (12)
N4550 6.2, 7.7, 8.6, 11.3, 11.9, 12.7 mm N4435
6.2, 7.7, 8.6, 11.3, 11.9, 12.7, 16.4 mm
also ArII7 mm, NeII12.8 mm, NeIII15.5 mm,
H2S(1)17.04 mm SIII18.7 mm
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M87 a young nuclear population?