We have used the ESO NTT/EMMI and VLT/FORS1 instruments to examine the LMC supernova remnant 0540-69.3 as well as its pulsar ( PSR B0540-69 ) and pulsar-powered nebula in the optical range .
Spectroscopic observations of the remnant covering the range of 3600 - 7350 Å centered on the pulsar produced results consistent with those of Kirshner et al .
( 1989 ) , but also revealed many new emission lines .
The most important are [ Ne III ] \lambda \lambda 3869 , 3967 and Balmer lines of hydrogen .
In both the central part of the remnant , as well as in nearby H II regions , the [ O III ] temperature is higher than \sim 2 \times 10 ^ { 4 } K , but lower than previously estimated .
For PSR B0540-69 , previous optical data are mutually inconsistent : HST/FOS spectra indicate a significantly higher absolute flux and steeper spectral index than suggested by early time-resolved groundbased UBVRI photometry .
We show that the HST and VLT spectroscopic data for the pulsar have \phantom { \geq } \smash { \buildrel \over { \lower 2.675022 pt \hbox { $ \buildrel% \lower 2.140017 pt \hbox { $ \displaystyle > $ } \over { \sim } $ } } } 50 % nebular contamination , and that this is the reason for the previous difference .
Using HST/WFPC2 archival images obtained in various bands from the red part of the optical to the NUV range we have performed an accurate photometric study of the pulsar , and find that the spectral energy distribution of the pulsar emission has a negative slope with \alpha _ { \nu } = 1.07 ^ { +0.20 } _ { -0.19 } .
This is steeper than derived from previous UBVRI photometry , and also different from the almost flat spectrum of the Crab pulsar .
We also estimate that the proper motion of the pulsar is 4.9 \pm 2.3 mas yr ^ { -1 } , corresponding to a transverse velocity of 1190 \pm 560 ~ { } km~ { } s ^ { -1 } , projected along the southern jet of the pulsar nebula .