ROSAT HRI observations of NGC 4038/4039, ''The Antennae'' galaxies

This paper presents data extracted from an image of the merging galaxies NGC 4038/39 obtained with the ROSAT High-Resolution Imager (HRI). This 5 ''-resolution image reveals complex and intricate X-ray emission associated with both galaxies, including: (1) regions of almost filamentary emission, closely following the H alpha distribution and generally related with star-forming regions; (2) emission peaks coincident with H II regions; (3) three possibly pointlike super-Eddington sources with L(X) greater than or similar to 4 x 10(39) ergs s(-1); and (4) prominent nuclear emission peaks with L(X) near similar to 10(40) ergs s(-1). Estimates suggest that X-ray emission from early-type stars in these galaxies is a small component of the total emission. Most of the observed X-ray emission can probably be explained as a combination of emission from discrete luminous evolved X-ray sources (binaries and supernova remnants) and from a diffuse hot interstellar medium (ISM). The morphology of the image suggests that there may be both nuclear outflows analogous to those observed in other starburst galaxies (e.g., NGC 253) and superbubbles (as, e.g., in LMC). The latter, however, would be 100-400 times more luminous than analogous features observed in the LMC and in M101.