The Radio Emission from Normal Galaxies: I. Observations of M31 and M33 at 158 Mc/s and 237 Mc/s

Open Access
Publisher Website
Google Scholar
Abstract
A survey of the radio emission from bright normal galaxies has been carried out at 158 Mc/s. This paper reports the results obtained on M31 and M33. The integrated radio magnitude ( m r ) of these two galaxies has been measured and compared with their photographic magnitude ( m p ); it is found that the difference ( m r – m p ) is almost the same for both. The distribution of intensity across M31 shows two major components: a disk and a corona . The corona is responsible for 90 per cent of the total emission, has a true axial ratio of about 0.6, and has a major axis which is about three times greater than that of the visible nebula. The results show that M33 also has a corona; the ellipticity, emissivity and dimensions of the corona relative to the visible object are closely similar to the values found for M31. A comparison between M31, M33 and the Galaxy suggests that the emissivity of the corona of the Galaxy is significantly higher than that of the other two galaxies.

This publication has 0 references indexed in Scilit: