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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.

Storing the files#

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

After downloading the isochrone files from whichever service chosen, these need to be stored in a folder named after the service used to produce them. It is important to use the correct name of the service used to generate the file(s), so that the isochrones class can then load the files properly.

The block below shows how the files should be stored for each service. A single > character points to a folder, while two >> characters point to a file.

> PARSEC/
  |---> phot_syst/
        |-------->> mets_ages.dat

> MIST/
  |---> phot_syst/
        |-------->> met_age_1.iso.cmd
        |-------->> met_age_2.iso.cmd
        |-------->> ...

> BASTI/
  |---> phot_syst/
        |--------> met_1/
                   |---->> age_1.isc_xxxx
                   |---->> age_2.isc_xxxx
                   |---->> ...
        |--------> met_2/
                   |---->> age_1.isc_xxxx
                   |---->> ...

In this example phot_syst is the name of the photometric system that is being employed (not required but suggested), mets_ages is the single file produced by the PARSEC service, met_age_X.iso.cmd is the name of a file produced by the MIST system, and age_X.isc_xxxx is the names of a file produced by the BASTI system, stored in a sub-folder named after its metallicity met_x.

Loading the files#

Once the files are properly stored in a folder, you need to load them by generating an isochrones object. You can generate an isochrones object as follows:

import asteca

# Load PARSEC isochrones
isochs = asteca.isochrones(
    isochs_path="parsec/",
    magnitude={"Gmag": 6390.21},
    color={"G_BPmag": 5182.58, "G_RPmag": 7825.08}
)

Where:

isochs (str)     : Path to the folder where the isochrone file(s) is(are) stored

magnitude (dict) : Name of the magnitude column in the isochrone file(s), followed by
its effective lambda value in angstrom units (see below)

color (dict)     : Name of the two magnitudes that make up the color, along with their
lambda values. Magnitudes must be **in the proper order**.

The effective lambda values represent the effective central/midpoint wavelength of a filter. These values are available for example in the CMD service.

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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