AN X-RAY IMAGE OF THE FORNAX DWARF SPHEROIDAL GALAXY

A ROSAT X-ray observation of the Fornax dwarf spheroidal galaxy is presented. A total of 19 sources are identified, one of which is a probable background galaxy cluster. This is consistent with the number expected due to the extragalactic background. Scaling in luminosity from normal ellipticals and bulges, we would expect to see at most one accreting binary source. This is consistent with our results, and implies that the IMF was not heavily biased towards massive stars. Scaling instead from globular clusters, we would expect eight sources in Fornax in the energy range 10(36)-10(38) erg s-1. We observe none. The low-density environment of the dwarf galaxy evidently does not produce a population of accreting neutron stars through star-star collisions. We place an upper limit of 4 X 10(-12) erg cm-2 s-1 on any diffuse gas component, corresponding to 10(5) M. of gas at 10(7) K. However, if heated to X-ray temperatures, gas could escape Fornax.