synthesizer.parametric.cosmic_sf_hist

A submodule for creating and manipulating cosmic star formation histories.

NOTE: These differ from other parametric SFHs in that the relative star

formation rate is tied to the age of the universe. They are therefore redshift dependent, so the redshift must be set consistently when a CSFH object is used to construct a Galaxy.

NOTE: This module is imported as CSFH in parametric.__init__ enabling the

syntax shown below.

Example usage:

from synthesizer.parametric import CSFH

print(CSFH.parametrisations)

csfh = CSFH.MadauDickinson(…)

csfh.calculate_sfh()

Classes

class synthesizer.parametric.cosmic_sf_hist.MadauDickinson(redshift, b, c, d, cosmo, min_age=unyt_quantity(0, 'yr'), max_age=unyt_quantity(1.e+11, 'yr'), n_grid=1000)

The Madau & Dickinson (2014) cosmic star formation history.

The shape of the cosmic star formation history is parametrised as

psi(z) = (1 + z)^b / (1 + ((1 + z) / c)^d),

and converted to a function of stellar age using a redshift grid.

redshift

The redshift at which the SFH is observed.

Type:

float

b

The low redshift power law slope.

Type:

float

c

The turnover in (1 + z).

Type:

float

d

The high redshift power law slope.

Type:

float

cosmo

The cosmology used to convert between age and redshift.

Type:

astropy.cosmology

min_age

The age below which the star formation history is truncated.

Type:

float

max_age

The age above which the star formation history is truncated.

Type:

float

t_univ

The age of the universe at the observation redshift (in years).

Type:

float

finegrid

The age grid (in years) on which the SFH is stored.

Type:

np.ndarray of float

intsfh

The SFH evaluated on finegrid.

Type:

np.ndarray of float