critical steps in population synthesis alessandro bressan magpop summer school - budapest, hungary,...
TRANSCRIPT
Critical Steps in
Population Synthesis
Alessandro Bressan
MAGPOP Summer School - Budapest, Hungary, 2006. August 23-25
What is Pop. Synth.An ensemble of tools used to predict properties of stellar systems
• resolved systems
C-M diagrams
• unresolved systems
Magnitudes (colours)
Spectra
Narrow band indices
Resolved system: Old Population
Resolved system: Young
Population
Resolved system:
“Complex” Population
Wide field imaging and Star Formation History in the Local Group Galaxies (Sagittarius)
Held et al 04
UnresolvedSystems
Bertone et al 05
The Isochrone
EVOLUTIONARYTRACKS
THEORETICAL ISOCHRONE
ISOCHRONEin the
OBSERVED SYSTEM
BOLOMETRICCORRECTIONS
MULTI BANDOBSERVATIONS OF
STARS
STELLARMODELS
• Y2 (Yonsei-Yale) Isochrones (Demarque, Yi et al. 83-06..)http://www.astro.yale.edu/demarque/yyiso.html
• Padova database of stellar evolutionary tracks and isochrones http://pleiadi.pd.astro.it/
Bertelli, Bressan, Chiosi, Girardi et al (84-06)
• GENEVA GRIDS OF STELLAR EVOLUTION MODELSMaeder, Meynet, Schaerer et al (84-06..)
http://obswww.unige.ch/~mowlavi/evol/stev_database.html
• Achim Weiss (http://www.mpa-garching.mpg.de/stars/index.shtml)
• Santi Cassisi (http://www.te.astro.it/osservatorio/personale/cassisi/)
• Oscar Straniero (http://www.te.astro.it/osservatorio/personale/straniero/oscar.html)
Phot. Systems
The Temperature scale
The Bolometric Corrections
Bertone et al 05
Isochrones
The C-M DiagramIsochrone IMF
C-M Diagram
Observationalm Effects:
• Completeness• Errors• Real Binaries• LOS Binaries
SSP
Case Study for the
Evolution of
Low Mass Stars:
Globular Cluster
NGC5024
Piotto et al 2002
Ev. Tracks with suited composition
No TP-AGB in Tracks!
Ev. Tracks vs. Isochrones
No Binaries- No Errors
10% Binaries
Errors & no Binaries
Errors and 5% Binaries
Errors & 20% Binaries
LF
IMF
Stellar Lifetimes
N(MV)
The Integrated Spectrum
EVOLUTIONARYTRACKS
STELLAR ATMOSPHERES
Theoretical Isochrone
Isochrone
Atmosph. Models vs Observ.
High Res Integrated Spectrum
Ca4227
G4300