Contours of X‐ray emission obtained with ROSAT HRI, overlaid on optical image of NGC 4038/39 (from SERC Southern Sky Survey J‐film, digitized at STScI); field of view is 17﹩\farcm﹩07 × 17﹩\farcm﹩07. Successive contours mark X‐ray surface brightnesses of 3, 6, 9, 12, and 15 σ above background. The X‐ray data have been binned into 1^{﹩\arcsec﹩} pixels and smoothed with a Gaussian of σ = 4^{﹩\arcsec﹩}. The optical image shows the disks of NGC 4038 (top) and NGC 4039 (bottom) and the two tidal tails. The relatively bright star ~5^{﹩\arcmin﹩} NW of NGC 4038/39 and detected in X‐rays is SAO 157048 (m_v = 8.4, spectral type F8).