ASCA OBSERVATION OF 3 BRIGHT EARLY-TYPE GALAXIES - NGC-4472, NGC-4406, AND NGC-4636

We report ASCA 0.3-10 keV X-ray observations of three early type galax ies, NGC 4472, NGC 4406, and NGC 4636. The extended emission in these galaxies is well described by thin thermal emission from hot gas. The gas temperature is 0.92 +/- 0.02 keV for NGC 4472, 0.79 +/- 0.01 keV f or NGC 4406, and 0.73 +/- 0.02 keV for NGC 4636. The metal abundance f or NGC 4472, NGC 4406, and NGC 4636 are, under the assumption of solar ratios, 0.63 +/- 0.15, 0.45 +/- 0.10, and 0.38 +/- 0.07, respectively . Detailed analysis has allowed determination of the abundances of oxy gen, silicon, sulfur, and iron. The observed abundances axe consistent with the solar ratios. For NGC 4472 and NGC 4406 we also determined t he mean temperature of the gas producing the Si lines from the ratio o f the Si H to He-like lines and find it to be consistent with the cont inuum temperature. The X-ray temperature is in good agreement with the observed optical velocity dispersion, stellar density profile, and ga s density profile. Our data indicates that the supernova rate should b e less than one fifth of the nominal rate in early type galaxies. We d erive the mass of these systems within fixed angular scales and find t hat M/L > 40, confirming that elliptical galaxies are dark matter domi nated at large radii.