The Vela Pulsar in the Ultraviolet*

摘要

We describe time-tagged observations of the Vela pulsar (PSR B0833-45) with the HST STIS MAMA UV detectors. Using an optimal extraction technique, we obtain an NUV light curve and crude FUV phase-resolved spectra. The pulse is dominated by complex nonthermal emission at all phases. We obtain approximate spectral indices for the brightest pulse components, relate these to pulsations observed in other wave bands, and constrain the thermal surface emission from the neutron star. An upper limit on the Rayleigh-Jeans component at UV pulse minimum suggests a rather low mean surface temperature T 4.6 × 105(d300/R14.2)2 K. If confirmed by improved phase-resolved spectroscopy, this observation has significant impact on our understanding of neutron star interiors.