Session 55 - Supernova Remnants.
Oral session, Tuesday, January 14
Harbour A,

## [55.04] X-ray observations of two unusual' Supernova Remnants: CTB80 containing the 40 millisecond pulsar PSR1951+32, and W50 containing the peculiar source SS433.

S. Safi-Harb (U. Wisconsin, Madison)

CTB 80 amp; W50 are two unusual' supernova remnants (SNRs) since unlike the other composite remnants, their radio morphology presents pronounced asymmetric structures. The unusual' properties of these SNRs are to a large extent associated with the emission from the compact objects associated with them, and their X-ray emission is the key to a better understanding of their properties.

I intend to present the X-ray analysis of these two peculiar sources and their powering engines. CTB 80 contains a 40 millisecond isolated pulsar, PSR1951+32, emitting non-thermal X-rays, and powering a compact nebula which is resolved with the ROSAT HRI. It has also a synchrotron nebula extending few arcminutes east of the pulsar and overlapping the radio plateau. With the ROSAT PSPC, a large \leq 1^o emission region is also detected in the hard energy band. W50, long thought to be the largest galactic SNR, contains at its center the mini-AGN binary source SS433, famous for its two-sided jets. I will present the X-ray analysis of the eastern and western lobes of W50 with both the ROSAT PSPC as well as the ASCA GIS detectors, thus covering the 0.1 -- 10 keV energy range. The emission is elongated along the axis of the precession cone of the SS433 jets, with an enhancement of brightness at \sim 35^\prime from SS433. The X-ray emission out to the base of the radio ears' is characterized by a hard spectrum whose spectral parameters vary in the radial and lateral directions. With the ROSAT PSPC, there is also detection of a much softer X-ray emission coincident with the eastern radio `ear' at the interaction zone between the jets and the ambient medium.

Using the above analysis and correlating the X-ray maps with those at other wavelengths, I discuss the possibility for these remnants to be partly or entirely produced by their powering engines, and derive some physical parameters relevant to better understand their nature.

The author(s) of this abstract have provided an email address for comments about the abstract: samar@astrog.physics.wisc.edu