HII region mass functions

Class providing models of the H**ii** region mass function—the distribution of gas masses among star-forming regions within a galaxy. Methods return the cumulative distribution (fraction of H**ii** regions by count) and cumulative mass (fraction of H**ii** region gas by mass) between specified minimum and maximum masses. These distributions are used to model the emission-line properties and the interstellar medium structure of star-forming galaxies in on-the-fly output analysis.

Default implementation: hiiRegionMassFunctionRosolowsky2021

Methods

cumulativeDistributionFunction → double precision

Returns the cumulative distribution of the HII region mass function between a minimum and maximum mass.

  • double precision, intent(in ) :: massMinimum, massMaximum

cumulativeMass → double precision

Returns the cumulative mass from the HII region mass function between a minimum and maximum mass.

  • double precision, intent(in ) :: massMinimum, massMaximum

hiiRegionMassFunctionRosolowsky2021

An HII region stellar mass function class in which giant molecular clouds are assumed to turn a fixed fraction \(\epsilon=\)[epsilon] of their mass into stars, and the giant molecular cloud mass function is given by Rosolowsky et al. (2021):

\[\phi(M) \propto \left(\frac{m}{M}\right)^{\alpha} \exp\!\left(-\frac{m}{M}\right),\]

where \(M\) is the mass of giant molecular cloud, \(M_\mathrm{min}=\)[massMinimum] and \(M_\mathrm{max}=\)[massMaximum] and the minimum and maximum giant molecular cloud masses respectively, and \(\alpha=\)[exponent].

(Default implementation)

Parameters

  • [epsilon] (default 3.0d-2) — Fraction of giant molecular cloud mass turned into stars.

  • [exponent] (default -1.2d0) — Exponent of the differential mass function.

  • [massMinimum] (default 1.0d4) — Minimum mass of giant molecular clouds.

  • [massMaximum] (default 1.0d8) — Maximum mass ofgiant molecular clouds.

  • [massCutOff] (default 4.7d6) — Cut off mass of giant molecular clouds.