SUPERNOVA-REMNANTS IN THE MAGELLANIC CLOUDS .1. THE COLLIDING REMNANTS DEM L316

The Large Magellanic Cloud (LMC) supernova remnant (SNR) DEM L316 is o f considerable interest, as it shows two overlapping shells at radio a nd optical wavelengths. This morphology suggests that DEM L316 is in f act two SNRs, which may or may not be spatially connected. We have obs erved the DEM L316 remnants at optical, radio, and X-ray wavelengths i n order to address the question of whether the SNRs are interacting, a nd if so, whether a tunnel might have formed between the remnants, all owing them to equilibrate. Besides the connecting shell morphologies a t optical and radio wavelengths, our observations show enhanced [O III ] emission at the juncture between the shells, enhanced X-ray emission from one shell at that juncture, and a change in the structure of the magnetic fieId near the interaction region. These factors strongly im ply that the two remnants are indeed colliding. In addition, we have d one a detailed study on the physical properties of the remnants, inclu ding an examination of thermal and kinetic energies and of the balance of thermal and magnetic pressures.