Journal of Physical Studies 4(2), 225–235 (2000) DOI: https://doi.org/10.30970/jps.04.225 ENERGY DISTRIBUTION IN THE EMISSION SPECTRA OF HII REGION NUCLEUS IN THE BLUE COMPACT DWARF GALAXIES BEYOND λ 912 Å

B. Ya. Melekh

Astonomical Observatory of the Ivan Franko Lviv National University,
8 Kyrylo i Mefodii Str., Lviv, UA-79005, Ukraine
E-mail: melekh@astro.franko.lviv.ua

The energy distribution in the radiation spectrum of the HII region nuclei is calculated beyond the Lyman limit on the basis of the observed emission fluxes in the Н$_β$, $λ$4471НеI, $λ$4686НеII lines of the 43 HII regions in 37 blue compact dwarf galaxies. The computational procedure of the ionization spectrum is discussed and three versions of the solution to this problem are considered. The essense of this method lies in the principle of the ionization-recombination and thermal equilibrium of quanta emitted by an ionizating source and absorbed by gas in the HII region. The first version corresponds to the assumption concerning equal spectral slopes beyond the hydrogen and helium discontinuities (the emission fluxes at $λ$ 912, $λ$ 504, $λ$ 228Å\ and a spectral index $α$ are computed). The second version corresponds to the assumption of the absence of helium discontinuities (emission flux at $λ$ 912Å\ and a spectral index within each of the three wavelength bands $λ$$λ$ 912–504Å, $λ$$λ$ 504–228Å, $λ$$λ$228–22.8Å\ having been determined). The third version is similar to the second one. However, the energy distribution in the wavelength band $λ$$λ$ 228–22.8Å\ was determined from its dependence on the spectral index value in the wavelength band $λ$$λ$ 912–504Å\ which we obtained from the Schaerer and de Koter models of stellar atmospheres.

PACS number(s): 98.58.Hf, 97.10.Ex

ps pdf