AN X-RAY IMAGE OF THE FORNAX DWARF SPHEROIDAL GALAXY

A ROSAT X-ray observation of the Fornax dwarf spheroidal galaxy is pre sented. A total of 19 sources are identified, one of which is a probab le background galaxy cluster. This is consistent with the number expec ted due to the extragalactic background. Scaling in luminosity from no rmal ellipticals and bulges, we would expect to see at most one accret ing binary source. This is consistent with our results, and implies th at the IMF was not heavily biased towards massive stars. Scaling inste ad 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-densi ty environment of the dwarf galaxy evidently does not produce a popula tion 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 compone nt, corresponding to 10(5) M. of gas at 10(7) K. However, if heated to X-ray temperatures, gas could escape Fornax.