AnASCAStudy of the Supernova Remnant G39.2−0.3

We present the analysis of archival data from the Advanced Satellite forCosmology and Astrophysics} (ASCA) of the supernova remnant (SNR) G39.2-0.3.G39.2-0.3 has been sometimes characterized as a shell-like remnant in theliterature but our high-energy imaging and spectral analysis show theunambiguous composite nature of the remnant. We find that part of thecontribution to G39.2-0.3's X-ray emission is distinctly non-thermal, bestdescribed by a power law with a photon index ($2.53^{\rm +0.34}_{\rm -0.27}$).The region of emission is consistent with a point source (extension consistentwith the point spread function of the detector at the off-axis angle of theobservation) and is roughly defined by a circle of radius of about 4 arcmin. Asecond contribution comes from a thermal component which contributes fluxprimarily at low energies. Despite the absence of any pulsed emission detectedfrom the compact source, we argue that the emission is most probably due to arotating compact object that is powering the detected synchrotron nebula withinthe SNR. \\Comment: 21 pages, 3 figures, Accepted for publication in Ap