Flux and intensity

Flux and intensity#

This page summarizes two switches that control how PySME outputs synthetic spectra.

normalize_by_continuum#

normalize_by_continuum controls whether the synthetic spectrum is divided by the synthetic continuum:

  • True (default): output a continuum-normalized spectrum (usually for normalized observations)

  • False: keep flux-level output (usually for flux-calibrated observations)

Even when this is False, continuum fitting can still be enabled through cscale_flag.

specific_intensities_only#

specific_intensities_only controls whether PySME returns angle-dependent specific intensities or disk-integrated flux:

  • False (default): integrate specific intensities over the stellar disk and return flux

  • True: return specific intensities directly, without flux-level post-processing

    • Note that in this case, synthesize_spectrum will only return the specific intensities, not the sme object.

This is useful when you want the radiative-transfer output itself (as a function of angle), rather than only the final integrated spectrum.

Typical usage#

  • Normalized stellar spectrum fitting:

    • normalize_by_continuum = True

    • specific_intensities_only = False

  • Flux-calibrated analysis:

    • normalize_by_continuum = False

    • specific_intensities_only = False

  • Intensity-level diagnostics / custom integration:

    • specific_intensities_only = True

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