ROSAT and BeppoSAX evidence of soft X – ray excess emission in the Shapley supercluster : A 3571 , A 3558 , A 3560 and A 3562

Excess soft X–ray emission in clusters of galaxies has so far been detected for sources that lie along lines–of–sight to very low Galactic HI column density (such as Coma, A1795, A2199 and Virgo,NH ∼ 0.9−2.0×10 20 cm). We show that the cluster soft excess emission can be investigated even at higher NH , which provides an opportunity for investigating soft X–ray emission characteristics among a large number of clusters. The ROSAT PSPC analysis of some members of the Shapley concentration (A3571, A3558, A3560 and A3562, at NH ∼ 4− 4.5× 10 20 cm) bears evidence for excess emission in the 1/4 keV band. We were able to confirm the finding for the case of A3571 by a pointed SAX observation. Within the current sample the soft X-ray flux is again found to be consistently above the level expected from a hot virialized plasma. The data quality is however insufficient to enable a discrimination between alternative models of the excess low energy flux. Subject headings: galaxies:clusters:individual (A3571, A3558, A3560, A3562) – intergalactic medium