Photometry in the field of the Fornax dSph

Hodge (1961a,b) made the first more detailed investigation of the stellar distribution in the Fornax system and of its globular clusters. In order to check the transparency of the galaxy, i.e. to see if any internal absorption is present, he also counted the background galaxies seen through the system. His conclusion was that there is no significant amount of general absorbing material present.

During the last decade a new interest in dwarf spheroidal galaxies has arisen, in particular concerning their composition and evolution. Faber and Lin (1983) discussed dark matter in such galaxies, and presented mass-to-light ratios considerably larger than previously thought. Mateo et al (1991) found a high central dark matter density in the Fornax spheroidal. In a review article on dark matter by Ashman (1992) the problem is further discussed. New investigations on dark matter in galaxies belonging to this class are of obvious importance.

The Fornax spheroidal is dominated by very old stars. It is, however, shown by (i) the width of the giant branch in the colour-magnitude diagram, (ii) the presence of blue, faint stars and (iii) the existence of large numbers of luminous carbon stars, that star formation has been going on until at least around 3-5 Gyrs ago. Recent observations by Stetson et al (1998) show that the galaxy even seems to contain some very young stars, only 100 Myrs old.