Bibcode
Zurita, A.; Rozas, M.; Beckman, J. E.
Bibliographical reference
Astrophysics and Space Science, v. 276, Issue 2/4, p. 1015-1022 (2001).
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3
2001
Journal
Citations
3
Refereed citations
3
Description
Using high-quality H_α images of five spiral galaxies, we have
studied the luminosity and distribution of the emission from diffuse
ionized gas (DIG). The estimated DIG luminosities account for 25-60% of
the total H_α emission in each galaxy and analysis of the
distribution has shown that the DIG is highly correlated geometrically
with the most luminous HII regions of the galaxies. The power required
to ionize the DIG is very high. The mean ionization rates per unit
surface area of a galaxy disc are of the order of 10^7 cm^-2 s^-1. Lyman
continuum photons (Lyc) from OB asociations are the most probable
sources of this ionization. Here we propose a specific model for these
sources: we show that the Lyman photon flux that leaks out of the
density-bounded HII regions of the galaxies is more than enough to
ionize the measured DIG in the five galaxies analysed.