2 NEW SUPERNOVA-REMNANTS IN OB-ASSOCIATIONS IN THE LARGE MAGELLANIC CLOUD

We discovered two extended x-ray sources in a ROSAT PSPC observation p ointed at the H II region W9 in the Large Magellanic Cloud. These two sources are in the H II regions N4D and N9. The x-ray characteristics suggest that both might be supernova remnants (SNRs). Follow-up CCD im ages taken with interference filters show high [S II]/H'alpha ratios i n the optical nebulae of these x-ray sources, confirming the presence of high velocity shocks commonly seen in SNRs. These two sources are a lso detected in the radio continuum at 8.55 and 4.75 GHz; both appear nonthermal compared to nearby H II regions. The confirmation of these two SNRs demonstrates that many SNRs in or near H II regions have been overlooked in previous surveys, and that the ROSAT x-ray survey combi ned with an optical CCD imaging survey of the Magellanic Clouds would provide the most effective way to uncover SNRs.