Tutorial: Instanteous and Non Instantaneous Recycling - galacticusorg/galacticus GitHub Wiki
Galacticus tracks metals produced by stellar evolution. How this is done is controlled by the stellarPopulationProperties
parameter which selects between different ways of computing properties of stellar populations.
Choosing stellarPopulationProperties=instantaneous
will cause Galacticus to use the
instantaneous recycling approximation for all calculations of stellar
populations. The recycled fraction and metal yield are determined from the stellarPopulation
provided by a stellarPopulationSelector
.
Setting stellarPopulationProperties=noninstantaneous
causes Galacticus to use a fully
non-instantaneous, metal-depdendent calculation of recycling, metal
production and rates. These rates are determined from the stellarPopulation
provided by a stellarPopulationSelector
. However, it is possible to force this method to
operate in the instantaneous recycling approximation limit (which can be
useful for testing and comparison) by setting:
<stellarPopulations value="standard">
<!-- Force the calculation of recycling, yields etc. to -->
<!-- be done assuming instantaneous recycling -->
<instantaneousRecyclingApproximation value="true"/>
<!-- Set the recycled fraction and yield -->
<recycledFraction value="0.35"/>
<metalYield value="0.02"/>
</stellarPopulationProperties>
where the recycled fraction and metal yield are specified directly, or
<stellarPopulations value="standard">
<!-- Force the calculation of recycling, yields etc. to -->
<!-- be done assuming instantaneous recycling -->
<instantaneousRecyclingApproximation value="true"/>
<!-- Set the mass of stars which should be used as the -->
<!-- dividing line between long-lived and instantaneously -->
<!-- evolving in this approximation. -->
<massLongLived value="1.0"/>
<!-- Set the effective age of populations to use in this -->
<!-- approximation when computing SNe numbers. -->
<ageEffective value="13.8"/>
</stellarPopulationProperties>
in which case the recycled fraction and metal yield will be computed that all stars with mass greater than massLongLived
have fully evolved, and energy input (from stellar winds and supernovae) will be computed assuming that stellar populations instantaneously reach an age of ageEffective
.