Soft X-ray Emission from the Vela Supernova Remnant

A soft X-ray observation of the Vela Supernova Remnant is described. X-ray surface brightness maps of the Remnant are presented in three energy intervals, 0.15 - 0.5 keV, 0.5 - 1.0 keV, and 1.0 - 2.0 keV, and in two different spatial resolutions, 1° x 1°, and 40' x 40'. The maps show a vague shell structure, with two prominent emission regions and a third of somewhat less intensity. A new method for producing these maps is described. Spectral results are presented for the entire nebula and for the two prominent subregions. The spectra are found to be represented by the model of X-ray emission from a low density, high temperature plasma with abundances given by Allen (1973). Line emission, radiative recombination, and thermal bremsstrahlung are included. Narrow band measurements with a filter system reveal that the emission from O VIII is deficient by at least a factor of three; a possible explanation of this is considered. A search for X-ray pulsations from the Vela pulsar is described, and upper limits are given for any X-ray pulsations at the period observed for the radio pulsar