ASCA observation of M 87

Abstract

We present the ASCA results of spatially resolved X-ray spectra in the central regions of the Virgo cluster, near to the central elliptical galaxy M 87 and 40′ northwest of M 87 (M 87 NW). Since the spectra of the M 87 region is complex, an adequate fit requires at least two thin thermal-plasma components. The temperatures of the hot and cool components are approximately 3.0 and 1.3 keV, respectively, and the temperature of these components are both nearly constant over the central 10′ radius from the center of M 87. The spectrum of M 87NW, on the other hand, can be well fitted by a single thin thermal-plasma model of ∼ 2.7 keV temperature. The abundances of Fe, Si, and S rise towards the center of M 87, though the ratios of Si/Fe and S/Si remain constant. We also found, contrary to the Einstein results, that the abundance ratio of oxygen to iron (O/Fe) is smaller than the solar value. We found no strong nuclear activity from M 87.