vice.toolkit.hydrodisk.hydrodiskstars.mode

Type : str [case-insensitive] or None

Default : “diffusion”

Recognized Values

The following is a breakdown of how stellar populations migrate in multizone simulations under each approximation.

  • “diffusion”

    The orbital radius at times between birth and 13.2 Gyr are assigned via a sqrt(time) dependence, the mean displacement if stars migrated according to a random walk. Stellar populations spiral inward or outward with a smooth time dependence in this model.

  • “linear”

    Orbital radii at times between birth and 13.2 Gyr are assigned via linear interpolation. Stellar populations therefore spiral uniformly inward or outward from birth to final radii, with orbital radius changing more slowly for young stars than in the diffusion model, but more quickly for old stars.

  • “sudden”

    The time of migration is randomly drawn from a uniform distribution between when a stellar population is born and 13.2 Gyr. At times prior to this, it is at its radius of birth; at subsequent times, it is at its final radius. Stellar populations therefore spend no time at intermediate radii.

  • None

    Only supported for subclasses of the hydrodiskstars object, this should be used when the user intends to override the built-in migration assumptions and implement a different one. In these cases, the __call__ method should be overridden in addition to this attribute being set to None.

Note

The “post-processing” model from Johnson et al. (2021) [1] corresponds to setting the attribute simple = True in the milkyway object, inherited from the base class multizone.

Example Code

>>> from vice.toolkit.hydrodisk import hydrodiskstars
>>> import numpy as np
>>> example = hydrodiskstars(np.linspace(0, 20, 81))
>>> example.mode
'diffusion'
>>> example.mode = "sudden"
>>> example.mode = "linear"