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Loading the isochrones

Loading the isochrones#

ASteCA requires a set of theoretical isochrones to estimate the fundamental parameters for the clusters. The supported services are: PARSEC, MIST, and BASTI.

Each service produces the isochrone files in a different way. A single file produced with these services will contain:

  • PARSEC : multiple metallicities and multiple ages

  • MIST : single metallicity and multiple ages

  • BASTI : single metallicity and single age

Loading the files#

All isochrones files should be stored in a single folder. ASteCA assumes that all files within that folder are isochrone files that should be loaded. The user can combine files for different photometric systems as long as they belong to the same service, i.e. PARSEC, MIST, or BASTI. The only restriction is that the files must have the same shape, this is: the same number of metallicities, ages, and initial masses.

To load the isochrones and generate an isochrones object, we proceed as follows:

import asteca

# Load PARSEC isochrones
isochs = asteca.isochrones(
    model="PARSEC",
    isochs_path="isochrones/",
    magnitude="Gmag",
    color=("G_BPmag", "G_RPmag"),
    magnitude_effl=6390.7,
    color_effl=(5182.58, 7825.08),
)

Where:

  • model : Model used to generate the isochrones. Must be one of the three allowed models

  • isochs_path : Path to the folder where the isochrone file(s) is(are) stored

  • magnitude : Name of the magnitude column in the isochrone file(s)

  • color : Name of the two filters that make up the color. Names must be in the proper order, i.e. such that the color name is generated by subtracting the first filter from the second one.

  • magnitude_effl : Effective lambda (in Angstrom) for the magnitude filter.

  • color_effl : Effective lambdas for the filters that make up the color.

The effective lambda values represent the effective central/midpoint wavelength of a filter. These values are returned by the CMD service, and are also available in the documentation for the pyphot package and the Filter Profile Service of the Spanish Virtual Observatory.

See asteca.isochrones for more information on the arguments of the isochrones class.

Please contact me if you have any issues with the loading process of the theoretical isochrones.

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