analysis.equivalent_width

The equivalent_width module measures the pseudo equivalent widths of observed and modeled spectra.

Function Documentation

exception analysis.equivalent_width.UnobservedFeature

Referencing a spectral feature that is at least partially unobserved.

analysis.equivalent_width.calc_pew(wavelength, flux, feature=None, feat_start=None, feat_end=None)

Generic function for calculating the pseudo equivalent width

If feat_start and feat_end are given, use them to determine the continuum flux. If they aren’t specified by feature is, estimate the boundaries of the feature.

Parameters:

• wavelength (ndarray) – An array of wavelength values
• flux (ndarray) – An array of flux values
• feature (dict) – A dictionary defining feature parameters
• feat_start (float) – The starting wavelength of the feature
• feat_end (float) – The ending wavelength of the feature

Returns:

The pseudo equivalent width as a float

analysis.equivalent_width.fit_continuum_func(wavelength, flux, feat_start, feat_end)

Fit the pseudo continuum for a given feature

Parameters:

• wavelength (ndarray) – An array of wavelength values
• flux (ndarray) – An array of flux values
• feat_start (float) – The starting wavelength of the feature
• feat_end (float) – The ending wavelength of the feature

Returns:

A linear function fit to the flux values bounding a feature

analysis.equivalent_width.get_feature_bounds(wavelength, flux, feature)

Get the start and end wavelengths / flux for a given feature

Parameters:

• wavelength (ndarray) – An array of wavelength values
• flux (ndarray) – An array of flux values
• feature (row) – A dictionary defining feature parameters

Returns:

The starting wavelength of the feature The ending wavelength of the feature

analysis.equivalent_width.tabulate_peak_model_pew(models)

Tabulate the pew for each feature at time of B band maximum

Parameters:models (list) – A list of sncosmo models Returns:A table of equivalent widths for each feature

analysis.equivalent_width.tabulate_pew_spectra(data_release, models=(), fix_boundaries=True)

Tabulate the pseudo equivalent widths for multiple spectra / features

Parameters:

• data_release (module) – An sndata data release
• models (list) – A list of sncosmo models
• fix_boundaries (bool) – Fix feature boundaries to observed values

Returns:

A table of equivalent widths over time

analysis.equivalent_width.tabulate_pew_spectrum(phase, wave, flux, models=(), fix_boundaries=True)

Tabulate the observed and modeled pew for multiple features

Parameters:

• phase (float) – The phase of the observed spectrum
• wave (ndarray) – An array of wavelength values
• flux (ndarray) – An array of flux values
• models (list) – A list of sncosmo models
• fix_boundaries (bool) – Fix feature boundaries to observed values

Returns:

An astropy table