vice.milkyway.mass_loading

Type : <function>

Default : vice.milkyway.default_mass_loading

The mass-loading factor as a function of galactocentric radius in kpc describing the efficiency of outflows. For a given star formation rate \(\dot{M}_\star\) and an outflow rate \(\dot{M}_\text{out}\), the mass-loading factor is defined as the unitless ratio:

\[\eta \equiv \dot{M}_\text{out} / \dot{M}_\star\]

This function must return a non-negative real number for all radii defined in the disk model.

Note

This formalism assumes a time-independent mass-loading factor at each radius. To implement a time-dependent alternative, users should modify the attribute eta of the singlezone objects corresponding to each annulus in this model. See example below.

See also

vice.singlezone.eta

Example Code

>>> import math as m
>>> import vice
>>> mw = vice.milkyway(name = "example")
>>> def f(r):
        return 0.5 * m.exp(r / 3)
>>> mw.mass_loading = f
>>> def g(t): # a time-dependent mass-loading factor
        return 3.0 * m.exp(-t / 3)
>>> # assign each individual annulus a time-dependent value
>>> for i in range(mw.n_zones):
>>>     mw.zones[i].eta = g