X-ray observations to detect hot coronae around galaxies

X-ray observations were made of two nearby edge-on spiral galaxies with the Imaging Proportional Counter (IPC) on the Einstein Observatory in an effort to detect hot (10/sup 6/ K), gaseous galactic coronae. No diffuse emission from galactic coronae was detected. Upper limits to diffuse emission (0.3--2.9 keV) are 1 x 10/sup 39/ ergs s/sup -1/ (NGC 3628) and 2 x 10/sup 38/ ergs s/sup -1/ (NGC 4244). The measurements indicate that less than 10/sup -3/ of the energy supplied by supernovae in these galaxies appears as soft X-rays. The energy from supernovae may be radiated away by cool gas (T<6 x 10/sup 5/ K) whose emission is undetectable by the Einstein Observatory, or the energy may be carried away by a hot wind (10/sup 7/ K) which radiates inefficiently. Serendipitous X-ray sources from the two IPC fields are listed.