On the corona of M87

Abstract

East-west drift scans of M87 performed by pulse-counting techniques with a 91-cm reflector are analyzed. Derivation of a mean luminosity profile in accord with the inverse-fourth-power law yields evidence of a faint coronal component in excess of the extrapolated luminosity distribution. The data are shown to be consistent with the suggestion that the excess luminosity in the outer coronae of elliptical galaxies is caused by tidal interaction with neighbors.