We investigate the X-ray properties of the powerful radio galaxy Hercules A (3C 348) using ROSAT HRI, PSPC and ASCA observations. The ASCA data are well fit by a thermal plasma model with a temperature of about 4.3 keV and abundances 0.4 solar. The HRI observation clearly reveals extended and elongated X-ray emission. For radii greater than 10 arcsec, the surface brightness profile perpendicular to the elongation is well fit by an isothermal beta--model with beta = 0.63 and a core radius of about 120 kpc. We derive a total mass of the putative cluster of 8.4e+13 M_sun and a gas mass fraction of about 18 per cent. The inner part of the surface brightness profile clealry reveals the presence of a point source, which contributes about 8 per cent to the total flux. The 0.1-2.4 keV luminosity of the point-like and the extended emission is 3.4e+43 and 4.3e+44 erg/s, respectively. After subtracting the cluster X-ray emission from the HRI image, residual structures are visible, which partly coincide with the radio jet and lobes. This indicates an interaction of the radio jet with the intracluster medium.
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