SED module (progenitors.sed)

SED fitting and plotting: fit stellar parameters from photometry using blackbodies, Pickles, MIST, BPASS, or red supergiant models. Supports MCMC (emcee) and nested sampling (dynesty).

Analysis (sed_fitter, emcee, dynesty)

Synphot compatibility layer

Synphot compatibility layer for progenitors.sed.

Provides a uniform API on top of synphot for spectra, bandpasses, and observations. Public API: setref, get_spectral_data_root, ArraySpectrum, BlackBody, Observation, ObsBandpass, ArrayBandpass, FileSpectrum. Uses synphot; HST/JWST filters require stsynphot.

progenitors.sed.synphot_compat.setref(area=None)

No-op for compatibility with legacy code.

synphot passes area to countrate() when needed; not used for magnitude calculations.

Parameters:

area (float, optional) – Telescope area (ignored).

progenitors.sed.synphot_compat.get_spectral_data_root()

Root directory for spectral data (e.g. Pickles, CDBS grid).

Prefers SYNPATH (synphot convention); falls back to PYSYN_CDBS (stsynphot/legacy). Returns empty string if neither is set.

Return type:

str

progenitors.sed.synphot_compat.ArraySpectrum(wave, flux, waveunits='angstrom', fluxunits='flam', name='')

Build a spectrum from wavelength and flux arrays (synphot backend).

Returns a wrapper with .wave, .flux, .name.

Parameters:

• wave (array-like) – Wavelength values.

• flux (array-like) – Flux values (same length as wave).

• waveunits (str, optional) – Wavelength unit (e.g. ‘angstrom’, ‘nm’). Default is ‘angstrom’.

• fluxunits (str, optional) – Flux unit: ‘flam’, ‘fnu’, ‘count’/’counts’, or astropy unit string. Default is ‘flam’.

• name (str, optional) – Label for the spectrum.

Returns:

Object with .wave, .flux, .name and .convert(unit) method.

Return type:

_SpectrumWrapper

progenitors.sed.synphot_compat.BlackBody(temp)

Blackbody spectrum at given temperature (synphot backend).

Returns wrapper; use .convert(‘fnu’) then scale.

Parameters:

temp (float) – Temperature in Kelvin.

Returns:

Normalized blackbody with .wave, .flux.

Return type:

_SpectrumWrapper

progenitors.sed.synphot_compat.Observation(spectrum, bandpass, binset=None, force='taper', **kwargs)

Observe a spectrum through a bandpass (synphot backend).

Use .effstim(‘abmag’) or .effstim(‘vegamag’).

Parameters:

• spectrum (_SpectrumWrapper or SourceSpectrum) – Source spectrum.

• bandpass (SpectralElement or array bandpass) – Filter bandpass.

• binset (array-like, optional) – Wavelength set for integration.

• force (str, optional) – If ‘taper’, taper bandpass edges. Default is ‘taper’.

Returns:

Object with .effstim(flux_unit) returning a float (e.g. magnitude).

Return type:

_ObservationWrapper

progenitors.sed.synphot_compat.ObsBandpass(name)

Load a named filter bandpass.

Uses synphot for standard names; stsynphot for HST/JWST (e.g. wfc3,uvis1,f438w).

Parameters:

name (str) – Filter name (e.g. ‘johnson,V’, ‘wfc3,uvis1,f438w’).

Returns:

Bandpass transmission curve.

Return type:

SpectralElement

Raises:

ImportError – If HST/JWST filter requested and stsynphot is not installed.

progenitors.sed.synphot_compat.ArrayBandpass(wave, trans, name='', waveunits='Angstrom')

Build a bandpass from wavelength and transmission arrays.

Parameters:

• wave (array-like) – Wavelength values.

• trans (array-like) – Transmission (0-1) at each wavelength.

• name (str, optional) – Unused; for API compatibility.

• waveunits (str, optional) – Wavelength unit. Default is ‘Angstrom’.

Returns:

Bandpass for use with Observation.

Return type:

SpectralElement

progenitors.sed.synphot_compat.FileSpectrum(filename)

Load a spectrum from a file (synphot backend; e.g. FITS).

Parameters:

filename (str) – Path to spectrum file.

Returns:

Object with .wave, .flux, .name.

Return type:

_SpectrumWrapper

Raises:

OSError, FileNotFoundError – If file cannot be opened.

Dust and RSG utilities

Constants

SED plotting and fitting constants.

Includes colors (RGB tuples), physical constants (e.g. SOLAR_LUM_CGS, BB_SCALE), dust/RSG scaling constants, and alternate column names for photometry tables.

progenitors.sed.constants.color(r, g, b)

Convert 0-255 RGB to (r, g, b, 1.0) tuple for matplotlib.

Parameters:

• r (int or float) – Red, green, blue in [0, 255].

• g (int or float) – Red, green, blue in [0, 255].

• b (int or float) – Red, green, blue in [0, 255].

Returns:

(r/255, g/255, b/255, 1.0).

Return type:

tuple

Utilities

SED utilities: dust maps, coordinate parsing, number formatting.

Core helpers live in progenitors.formatting_utils and progenitors.sfd_dust.

Plotting