Regions of source extraction superposed on X‐ray images smoothed for better display. (Counts were extracted from unsmoothed images and corrected for background as described in text). (a) Large‐field view showing apertures used for integrated counts of NGC 4038/39 (see Table 2) and for background determination; data have been binned into 2^{﹩\arcsec﹩} pixels and smoothed with σ = 4^{﹩\arcsec﹩} Gaussian. Extraction regions are also shown for X‐ray sources X‐13 (SAO 157048), X‐14 (source P in Read et al. 1995), X‐15 (source Q in Read et al. 1995) and X‐16. (b) Enlarged view of central region of NGC 4038/39 showing large circular‐aperture regions from Table 1; data have been binned into 2^{﹩\arcsec﹩} pixels and smoothed with σ = 4^{﹩\arcsec﹩} Gaussian. (c) View of central region showing small‐aperture and rectangular extraction regions from Tables 1 and 2 (X‐1, X‐7, and source E are from Read et al.); data have been binned into 1^{﹩\arcsec﹩} pixels and smoothed with σ = 2^{﹩\arcsec﹩} Gaussian.