X-ray emission from M87: A pressure confined cooling atmosphere surrounding a low mass galaxy

With a conventional model for the mass of the galaxy M87 (5 x 1011 M/sub sun/ at 100 kpc), we show that a radiative cooling flow agrees remarkably well with spectroscopically derived mass flow rates onto M87 (roughly-equal 10 M/sub sun/ yr-1) and surface brightness profiles of X-ray emission around the galaxy. Values of the density (approx. few x 10-4 cm-3) and temperature (approx. 108 K) in the diffuse cluster are obtained. No massive halo is required. The atmosphere of M87 contains approx. 1012 M/sub sun/ of gas and possesses a temperature profile which increases outward. This gas acts as a reservoir for the flow. We show that our model requires that the thermal conductivity in the atmosphere must be less than 1% of its classical value