POPULATION SYNTHESIS MODELS

readme file

last modification: 12 Nov 2008

This database contains the integrated spectra, integrated colours and Mass to Light (ML) ratios described in Percival, Salaris , Cassisi & Pietrinferni (2008, ApJ in press), for simple stellar populations (single-age, single-metallicity), based on the BaSTI isochrones, employing the Kroupa (2001, MNRAS, 322, 231) Initial Mass Function.

Integrated magnitudes and ML ratios are provided for UBVRIJHKL filters. Additional photometric systems can be easily accounted for by convolving the low resolution integrated spectra with the appropriate filter response curves, and using an appropriate normalizing spectrum (a Vega synthetic spectrum is available here ).

ML ratios tabulate also the amount of mass (in solar mass units) locked into evolving stars, white dwarfs (WDs), neutron stars (NSs) and black holes (BHs), to help determine ML ratios in any arbitrary photometric system.
We recall that the ML ratio is defined as the ratio between the integrated luminosity in a given passband (in solar units) divided by the integrated stellar mass (in solar units) contained in stars, including all remnants.
To compute the solar luminosity in the UBVRIJHKL we have adopted the following set of solar absolute magnitudes:

The mass contained in WD, NS and BH remnants has been computed by assuming an initial-final-mass (IFMR) relation in addition to the IMF. For WDs with a carbon-oxygen core we employed the IFMR obtained from our AGB modelling. The upper initial mass limit for the production of carbon-oxygen WDs (the so-called M^up) is also obtained from our stellar models. For initial masses between M^up and 10 solar masses we considered typical oxygen-neon core WDs with masses of 1.3 solar masses. Initial masses between 10 and 25 solar masses are assumed to give rise to 1.4 solar mass NSs, whereas for progenitors between 25Mo and 100Mo we consider a final state as BHs with mass equal to 1/3 of the initial mass.

We provide integrated properties for the isochrones including the full thermal pulse AGB evolution and we consider only the models including core-overshooting during the Main Sequence, for the appropriate age range. This is in our view the `best choice' to match the properties of observed stellar populations. Integrated properties for models without core overshooting and/or without the full thermal pulse phase are available upon request. The alpha-enhanced data are based on the isochrones calculated with the recommended F05 opacities.

The coding of the file names is as for the isochrones.

The tables of integrated magnitudes display, for a stellar population with total mass equal to 1Mo:

  1 column) the age of the population in Myr;
  2 column) the integrated magnitudes in U;
  3 column) the integrated magnitudes in B;
  4 column) the integrated magnitudes in V;
  5 column) the integrated magnitudes in R;
  6 column) the integrated magnitudes in I;
  7 column) the integrated magnitudes in J;
  8 column) the integrated magnitudes in H;
  9 column) the integrated magnitudes in K;
 10 column) the integrated magnitudes in L; 

The tables of ML ratios display:

  1 column) the age of the population in Myr;
  2 column) the ML ratio (in solar units) for the magnitude U;
  3 column) the ML ratio (in solar units) for the magnitude B;
  4 column) the ML ratio (in solar units) for the magnitude V;
  5 column) the ML ratio (in solar units) for the magnitude R;
  6 column) the ML ratio (in solar units) for the magnitude I;
  7 column) the ML ratio (in solar units) for the magnitude J;
  8 column) the ML ratio (in solar units) for the magnitude H;
  9 column) the ML ratio (in solar units) for the magnitude K;
 10 column) the ML ratio (in solar units) for the magnitude L;
 11 column) the total mass (in solar units) of the stars still evolving;
 12 column) the total mass (in solar units) locked in white dwarfs;
 13 column) the total mass (in solar units) locked in neutron stars;
 14 column) the total mass (in solar units) locked in black hole remnants;  

The tables of High Resolution integrated spectra for each combination of age and chemical composition display:

  1 column) wavelength  (Angstrom);
  2 column) flux/wavelength (arbitrary units);

The tables of Low Resolution integrated spectra for each combination of age and chemical composition display:

  1 column) wavelength   (nm);
  2 column) flux/wavelength (where the flux units are 
            4.3607• 10-33 erg•s-1•m-1 and wavelength units are m);

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