International Conference of Physicists.SPb, October 20-24, 2025, Saint Petersburg
Astronomy and Astrophysics

Simulation of the extended base of emission lines in the spectra of HII regions

Ya. O. Anan'ev^ab, O. A. Kurichin^a, A. V. Ivanchik<sup>a

a</sup> Ioffe Institute, St. Petersburg
^b Alferov Federal State Budgetary Institution of Higher Education and Science Saint Petersburg National Research Academic University of the Russian Academy of Sciences, St. Petersburg

Abstract: The profile of the additional broadened spectral component of the emission lines of the HII regions in the continuum region is modeled. A simple physical model is proposed to describe the emission profiles of the lines, and the simulation of the observed line profile on real spectrographs is carried out. It is shown that for processing SDSS and DESI data, the integral line profile associated with expanding shells can be described by a single Gaussian function. The test processing of the spectra, taking into account this effect, showed that neglecting the wide component when modeling line profiles can lead to an error in the measured fluxes by up to 10%, which, in turn, can lead to noticeable systematic shifts in estimates of the physical parameters of the HII regions. The proposed method can be included in the procedures for automatic processing and analysis of a large number of spectra with low and medium spectral resolution.

Keywords: emission lines, HII regions, dwarf galaxies.

Received: 05.05.2025
Revised: 28.07.2025
Accepted: 09.08.2025

DOI: 10.61011/JTF.2025.12.61795.239-25

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