Binaries from Afar: Impact on Integrated Photometry of Stellar Populations Peter Anders (Utrecht) with Rob Izzard (Brussels) 1
We want to study the impact of binaries in star clusters and galaxies! 2
We want to study the impact of binaries in star clusters and galaxies! 3 MWGC NGC 2419 Dalessandro et al. 2008
We want to study the impact of binaries in star clusters and galaxies! Star clusters 4 NGC 1569 Dwarf galaxy MWGCSBNGC 2419 D=2.2 Dalessandro etmpc al. 2008
Spectrophotometric models: What do we need? 5 stellar isochrones stellar atmosphere spectra emission line ratios stellar MF Star formation history (for galaxies only) filter response curves GALEV evolutionary synthesis models
And then? 6
What do we get? Quantities Integrated spectra and spectral features Integrated magnitudes in any filter you like (and have) Stellar mass (gas mass, gas metallicity)... As a function of Used isochrones & spectral library Age Metallicity Cluster/galaxy mass Extinction Stellar MF For galaxies: SFH, starbursts 7
Binary characteristics We need: Program which: Can evolve single and binary stars Through all relevant evolutionary phases For a range of input physics (i.e. metallicities) And binary parameter combinations In a reasonable amount of time BSE (Eggleton, Tout, Hurley, Izzard...) Binary parameters: Primary masses: in the range 0.1 80 M Secondary masses: in the range 0.1 M MP Mass ratio distribution: flat Eccentricity distribution: thermal 128^3 = 2.1 million models 8
Resulting isochrones 9
Resulting isochrones Single stars 10
Resulting isochrones Single stars 11 Binary stars
Results: colour evolutions 12
Results: colour evolutions 13
Results: colour evolutions 14
Results: age determination 15
Appendix: Behind the scenes: What do we really do? Take stellar isochrone Information about evolutionary stage of stars with different masses at a given age isochrones of Padova or Geneva group, our binary isochrones Assign a stellar atmosphere spectra to each star Library with large range of Teff, log(g), Z BaSel 2.2 library, high-resolution spectra in prep. Weigh with stellar IMF Number distribution of stellar masses Salpeter (1955), Kroupa (2001)... Add gaseous and line emission Ionizing flux from hot stars observed + theoretical (Account for SFH, galaxies only) Sum up contributions Integrated spectrum Convolve with filter response curves for integrated photometry 16
Appendix: Behind the scenes: What do we really do? Take stellar isochrone Information about evolutionary stage of stars with different masses at a given age isochrones of Padova or Geneva group, our binary isochrones Assign a stellar atmosphere spectra to each star Library with large range of Teff, log(g), Z BaSel 2.2 library, high-resolution spectra in prep. Weigh with stellar IMF Number distribution of stellar masses Salpeter (1955), Kroupa (2001)... Add gaseous and line emission Ionizing flux from hot stars observed + theoretical (Account for SFH, galaxies only) Sum up contributions Integrated spectrum Convolve with filter response curves for integrated photometry 17
Appendix: Behind the scenes: What do we really do? Take stellar isochrone Information about evolutionary stage of stars with different masses at a given age isochrones of Padova or Geneva group, our binary isochrones Assign a stellar atmosphere spectra to each star Library with large range of Teff, log(g), Z BaSel 2.2 library, high-resolution spectra in prep. Weigh with stellar IMF Number distribution of stellar masses Salpeter (1955), Kroupa (2001)... Add gaseous and line emission Ionizing flux from hot stars observed + theoretical (Account for SFH, galaxies only) Sum up contributions Integrated spectrum Convolve with filter response curves for integrated photometry 18
Appendix: Behind the scenes: What do we really do? Take stellar isochrone Information about evolutionary stage of stars with different masses at a given age isochrones of Padova or Geneva group, our binary isochrones Assign a stellar atmosphere spectra to each star Library with large range of Teff, log(g), Z BaSel 2.2 library, high-resolution spectra in prep. Weigh with stellar IMF Number distribution of stellar masses Salpeter (1955), Kroupa (2001)... Add gaseous and line emission Ionizing flux from hot stars observed + theoretical (Account for SFH, galaxies only) Sum up contributions Integrated spectrum Convolve with filter response curves for integrated photometry 19
Appendix: Behind the scenes: What do we really do? Take stellar isochrone Information about evolutionary stage of stars with different masses at a given age isochrones of Padova or Geneva group, our binary isochrones Assign a stellar atmosphere spectra to each star Library with large range of Teff, log(g), Z BaSel 2.2 library, high-resolution spectra in prep. Weigh with stellar IMF Number distribution of stellar masses Salpeter (1955), Kroupa (2001)... Add gaseous and line emission Ionizing flux from hot stars observed + theoretical (Account for SFH, galaxies only) Sum up contributions Integrated spectrum Convolve with filter response curves for integrated photometry 20
Appendix: Behind the scenes: What do we really do? Take stellar isochrone Information about evolutionary stage of stars with different masses at a given age isochrones of Padova or Geneva group, our binary isochrones Assign a stellar atmosphere spectra to each star Library with large range of Teff, log(g), Z BaSel 2.2 library, high-resolution spectra in prep. Weigh with stellar IMF Number distribution of stellar masses Salpeter (1955), Kroupa (2001)... Add gaseous and line emission Ionizing flux from hot stars observed + theoretical (Account for SFH, galaxies only) Sum up contributions Integrated spectrum Convolve with filter response curves for integrated photometry 21