Search for the optical counterpart of the 16ms X-ray pulsar in the LMC

The 16ms X-ray pulsar PSRJ0537-6910 in SNR N157B is the fastest known isola ted (non-recycled) pulsar and, with a rotational energy loss (E) over dot s imilar to 4.8 x 10(38) erg s(-1),is the most energetic (together with the C rab). Here we report the results of optical observations of the field, rece ntly performed with the SUSI2 camera of the NTT. Few objects are observed i nside the similar or equal to 3 " X-ray error circle but none of them can b e convincingly associated to the pulsar, which appears undetected down to V similar to 23.4. With a corresponding optical luminosity L-opt less than o r equal to 1.3 x 10(33) erg s(-1), PSRJ0537-6910 is, at best, comparable to the other very young pulsars Crab and PSR BO540-69.