High-Resolution Optical Imaging of the Large Magellanic Cloud Plerion 0540-69

The Crab-like SNR 0540-69 in the LMC has been investigated using the ESO NTT (New Technology Telescope) equipped with SUSI (SUperb Seeing Imager). B, V, O III, S II, and Hα images were collected under very good seeing conditions, yielding unprecedented detail on the picture of the expanding shell as well as of the synchrotron nebula, which is shown to harbor two maxima of emission. Both of these are seen to have magnitudes comparable to that of the optical pulsar reported by Middleditch et al. (1987), the northern one appearing more compact. The Hα image shows previously unseen structures, apparently unrelated to the expanding shell as well as to the synchrotron nebula. The Hα extent of the remnant is significantly smaller than that at other wavelengths and shows a symmetric pattern centered on the northern maximum of continuum emission which could very well be the optical counterpart of PSR 0540-69.