NGC 1427A - an LMC type galaxy in the Fornax Cluster

Abstract

We have discovered that the Fornax irregular galaxy NGC 1427A is in very many respects a twin of the Large Magellanic Cloud. Based on B, V, I, and H alpha images, we find the following. The light of the galaxy is dominated by high surface brightness regions in the south-west that are superimposed by a half-ring of OB associations and H II regions indicating recent star formation. The colors of the main stellar body are (V-I) = 0.8 mag and (B-V) = 0.4 mag, comparable to the LMC colors. A low surface brightness cloud north of the main body as well as a LSB tail in the west have colors (V-I = 0.2 mag) that are more typical for blue compact dwarf galaxies. We identified a system of cluster candidates with mean ages < 2 Gyr (assuming a LMC metallicity) comprising the richest cluster system in an irregular galaxy observed up to now outside the Local Group. In X-ray wavelengths NGC 1427A appears with a relatively soft and complex spectrum.