Modelling of radio emission from normal galaxies at low radio frequencies

In this paper we present results from modelling of the low frequency radio emission from galaxies with similar characteristics to the Milky Way with represantive distance of 1 Mpc. In modelling we considered observational effects as galaxy orientation (inclination). Results are presented in the form of global and local (from galaxy centre) spectrum. The radio emission of normal galaxies may become opaque at low frequencies due to thermal ionized gas. According to our results ionized gas similar to the Milky Way ionized gas may be responsible for flattening of radio spectra. We argue that global spectra from galaxies do not change their shape at higher frequencies with disk orientation along the line of sight even in galaxies with higher thermal fractions. Only the low frequency part of total spectrum is sensitive to galaxy inclination. The flattening of total radio spectrum seems to be more possible in edge-on than face-on galaxies. We also show that the local spectrum from galaxy center has clear turn-over at a few MHz only for galaxies with higher inclination.