Key points are not available for this paper at this time.
Soft X-ray images of the M87 region were obtained using the Einstein Observatory imaging proportional counter. The 0.7-3.0 keV surface brightness of M87 was mapped to a radial distance exceeding 50 arcmin where it falls 2.5 orders of magnitude below its peak value. The temperature profile of the hot (about 2.5 keV) gas responsible for the X-ray emission was determined from the X-ray spectral data; the gas temperature is approximately constant between radii of 6 and 20 arcmin, but decreases at radii less than 6 arcmin; beyond 20 arcmin, a negative temperature gradient is excluded. Because this gas responds to the gravitational potential of M87, the X-ray observations can be used to measure the radial mass distribution in M87.
Fabricant et al. (Wed,) studied this question.