astLib.astSED.StellarPopulation

This class describes a stellar population model, either a Simple Stellar Population (SSP) or a Composite Stellar Population (CSP), such as the models of Bruzual & Charlot 2003 or Maraston 2005.

The constructor for this class can be used for generic SSPs or CSPs stored in white space delimited text files, containing columns for age, wavelength, and flux. Columns are counted from 0 ... n. Lines starting with # are ignored.

The classes M05Model (for Maraston 2005 models), BC03Model (for Bruzual & Charlot 2003 models), and P09Model (for Percival et al. 2009 models) are derived from this class. The only difference between them is the code used to load in the model data.

getSED(self, ageGyr, z=0.0, normalise=False, label=None)

source code

Extract a SED for given age. Do linear interpolation between models if necessary.

Parameters:

ageGyr (float) - age of the SED in Gyr
z (float) - redshift the SED from z = 0 to z = z
normalise (bool) - normalise the SED to have area 1

Returns: SED object

SED

getColourEvolution(self, passband1, passband2, zFormation, zStepSize=0.05, magType="Vega")

source code

Calculates the evolution of the colour observed through passband1 - passband2 for the StellarPopulation with redshift, from z = 0 to z = zFormation.

Parameters:

passband1 (Passband object) - filter passband through which to calculate the first magnitude
passband2 (Passband object) - filter passband through which to calculate the second magnitude
zFormation (float) - formation redshift of the StellarPopulation
zStepSize (float) - size of interval in z at which to calculate model colours
magType (string) - either "Vega" or "AB"

Returns: dictionary

dictionary of numpy.arrays in format {'z', 'colour'}

getMagEvolution(self, passband, magNormalisation, zNormalisation, zFormation, zStepSize=0.05, onePlusZSteps=False, magType="Vega")

source code

Calculates the evolution with redshift (from z = 0 to z = zFormation) of apparent magnitude in the observed frame through the passband for the StellarPopulation, normalised to magNormalisation (apparent) at z = zNormalisation.

Parameters:

passband (Passband object) - filter passband through which to calculate the magnitude
magNormalisation (float) - sets the apparent magnitude of the SED at zNormalisation
zNormalisation (float) - the redshift at which the magnitude normalisation is carried out
zFormation (float) - formation redshift of the StellarPopulation
zStepSize (float) - size of interval in z at which to calculate model magnitudes
onePlusZSteps (bool) - if True, zSteps are (1+z)*zStepSize, otherwise zSteps are linear
magType (string) - either "Vega" or "AB"

Returns: dictionary

dictionary of numpy.arrays in format {'z', 'mag'}

calcEvolutionCorrection(self, zFrom, zTo, zFormation, passband, magType="Vega")

source code

Calculates the evolution correction in magnitudes in the rest frame through the passband from redshift zFrom to redshift zTo, where the stellarPopulation is assumed to be formed at redshift zFormation.

Parameters:

zFormation (float) - redshift to evolution correct from
zTo (float) - redshift to evolution correct to
zFormation (float) - formation redshift of the StellarPopulation
passband (Passband object) - filter passband through which to calculate magnitude
magType (string) - either "Vega" or "AB"
zFrom (float)

Returns: float

evolution correction in magnitudes in the rest frame

Class StellarPopulation

getSED(self, ageGyr, z=0.0, normalise=False, label=None)

getColourEvolution(self, passband1, passband2, zFormation, zStepSize=0.05, magType="Vega")

getMagEvolution(self, passband, magNormalisation, zNormalisation, zFormation, zStepSize=0.05, onePlusZSteps=False, magType="Vega")

calcEvolutionCorrection(self, zFrom, zTo, zFormation, passband, magType="Vega")