A Voigt profile is the convolution of a Gaussian distribution and a Cauchy distribution. For an absorption line, thermal Doppler broadening contributes the Gaussian core while finite excited-state lifetime contributes the Lorentzian wings. Instrumental broadening and unresolved motions must also be modeled when inferring column density and temperature.
The Voigt profile is a mathematical function that describes the spectral line shape of light emitted or absorbed by atoms and molecules. It accounts for both Doppler broadening and pressure broadening (also known as collisional broadening). In more detail: - **Doppler Broadening** occurs due to the thermal motion of particles, which causes variations in the observed frequency of the spectral line based on the velocities of the emitting or absorbing species.
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