SSP vs Galaxies

Held et al 04

SSP:• Chemically Homogeneous • Coheval• Seldom affected by differential

extintion• Single IMF

•Variable IMF ?

Galaxy:•Complex chemistry•Age distribution

•Differential extinction

In space

In age

Chemo-Spectrophotometric Population Synthesis

First consistent chemo + stellar evolution + spectral code by Bressan et al 94Many other synth. tools, e.g. Bruzual & Charlot 90-06…, Jimenez et al 00… etc..

S: stellar birth ratef: star(M,,Z) spectrum

Without dust a bare integral !All difficulties in St. Evol. And St.

Atmosph. !!If S=t*m (Bruzual 86) then integrate SSP instead of single stars !

t & Z(t) provided by chemical evolution

)()(

)()(

*

tEtZM

tEtMg

ConstMMM

ZZ

g

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

0

Z

MM gInitial conditions

Um

tm mr dmmtmmtE)(

)()()()(

Um

tm mZm

A

mZmrZ dmmtmptZmpmmtE)(

)()()()()(

E(t): the rate of gas ejection by dying stars

mr is the mass of the remnantm 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

Instantaneous Recycling Appr.

• Stars with mass < mI (=1 MŸ) never day m = ∞

• Stars with mass ≥ mI have negligible lifetime m = 0

RttE

dmmmmRU

I

m

m r

)()(

)()(

• 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

R

dmmpmy

P

m

m Zm

Z

U

I

1

)(

)()](1)[1()()()( ttZRyRttZtE ZZ

)1)(()1()1)((

)1)((

ZtRyRtZM

RtMg

ZZ

)1

ln(

)()(

])([))](1()()[1)((

GyZ

Mg

MgyZ

yMgMgtZZMgMgtZ

ytZMgtZytZRtM

Z

Z

Z

ZZZ

For Z << 1:

NOTE: Independent from the mass of the galaxy

Other physics needed to interpret Z-Mass relations

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)

StellarYields

NSRM Yields computed adopting

ejecta (Mo) vs MCO of

Woosley &Weaver 95

From Portinari et al 98

SN Ia yieldsElement M/Mo

Nomoto et al 84

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)

Linear Trends

•For the thin disk :

•[Mg/Fe] = -0.37 [Fe/H] - 0.040 = 0.067 dex

•[/Fe] = -0.29 [Fe/H] - 0.029 = 0.052 dex

•For the thick disk :

•[Mg/Fe] = -0.41[Fe/H]+0.097, = 0.092 dex

•[/Fe] = -0.30[Fe/H]+0.071, = 0.069 dex

(from Soubiran & Girard 05)

Observations and Chemical Ev. Model for Solar Vicinity

Chemo-kinematical parameters for 424 stars Rocha-Pinto et al. 04

Cayrel et al 00

Need s

ome Y

ield a

djuste

ment !

!!!

corrected

Caffau et al. 06

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

NGC 4435• NGC 4435 is an SB0(7) in interaction

with NGC 4438 (spiral): nearest passage about 100 Myr ago

(Vollmer et al 05)

• MMBH BH by Coccato et al 05by Coccato et al 05• Opt. Pop. Study by Sarzi et al 05Opt. Pop. Study by Sarzi et al 05• MIR spectrum typical of a star star

forming objectforming object ( (sspiral NGCpiral NGC 7331)7331)

(Panuzzo et al 06)

UV+NIR+MIR+FIR + Radio

OLD + Starburst

GRASIL FIT

MC

Diffuse dust

OLDNGC4435

Best fit model of central 5” with GRASIL (Silva et al 98, Vega et al 05)

post post starburststarburst with residual SFR ~ 0.07 M⊙/yr

AgeAge ~ 180 Myr

< >SFR< >SFR ~ 0.7 M⊙/yr

MMBURSTBURST ~ 1.2 108 M⊙ ~ 1.5% M (5 GAL

)arcsec PAH model ( & 01Li Draine , 05Vega et al ) needs 14 revison above m

OldOld M ~ 8 109 M⊙ Age ~ 9 = 0.02Gyr Z

:Young:Young

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)

•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)

SSP in the MIR10µm10µm bump: bump:

Dusty AGB envelopes ?Dusty AGB envelopes ?

Emission Lines 2 galaxies (12%)

N4636 [NeII]12.8 m [NeIII]15.5 m [SIII]18.7 m

N4486 [ArII]7 m [NeII]12.8 m [NeIII]15.5 m [SIII]18.7 m

( M87 )

PAHs 2 Galaxies (12%)

N4550 6.2, 7.7, 8.6, 11.3, 11.9, 12.7 m

N4435 6.2, 7.7, 8.6, 11.3, 11.9, 12.7, 16.4 m also [ArII]7 m, [NeII]12.8 m, [NeIII]15.5 m, H2S(1)17.04 m [SIII]18.7 m

M87 a young nuclear population?

Total fluxes

Nuclear Fluxes

Total fluxes

Nuclear Fluxes