PHOTOMETRY AND PROPER MOTION OF THE VELA PULSAR

We present the first UBVR photometry of the Vela Pulsar. All observed colours lie significantly above any Rayleigh-Jeans extrapolation of th e ROSAT soft X-ray black body curve. While the U, B and V fluxes can b e described by a flat power law, the R point lies about 1 magnitude be low the expectation. An evidence for a similar spectral turnover, but at longer wavelength, was also claimed for the Crab Pulsar, another yo ung INS with non-thermal optical emission. However, to account for the Vela R point in term of synchrotron self absorption, the emission geo metry of the two pulsars must be different. In parallel, we have used the new images to re-assess the proper motion of the Vela pulsar, an e ffect for which vastly different results have been reported in the lit erature.