1997A&A...322...89P

We obtained a high spatial resolution image of Stephan's Quintet with the ROSAT HRI detector. The observations reveal that the extended X-ray emission from the compact group originates from several distinct components. The total X-ray luminosity in the 0.1-2keV band within a circle of 6' diameter is L_x∼5x10⁴¹erg/s. This measure is consistent with previous ROSAT PSPC observations. The new results indicate that only a fraction of the detected emission can be attributed to a diffuse, hot intergalactic medium and/or to individual members of the group. One third of the detected photons are concentrated in an intergalactic feature that closely matches one previously observed in the radio continuum. This structure is likely a manifestation of shocks resulting from the strong interactions or collisions occuring in the group. Individual galaxies are also detected: 1) coincident with the Seyfert 2 galaxy NGC 7319 and 2) with NGC 7318a. They contribute <20% of the total emission. A residual component with L_x∼2x10⁴¹erg/s is also detected which may be due to emission from more diffuse hot gas. The present observation reduces the X-ray luminosity that can be attributed to a diffuse intergalactic medium in this system. It limits the mass of any diffuse component to M_gas<3x10¹⁰M_☉. These results raise the possibility of the existance of two quite different intergalactic X-ray components in spiral-dominated compact groups.