BeppoSAX-ROSAT PSPC observations of the Shapley supercluster: A3562

We present a combined analysis of the BeppoSAX and ROSAT PSPC observation o f the cluster of galaxies A3562, a massive member of the core of the Shaple y supercluster. With a complex and interacting structure composed from two groups of galaxies and A3558 to the west, the surface brightness of A3562 s hows excess in the sectors to east and south when compared with an azimutha lly averaged model of the emission. The emission tends to be flatter, and t he distribution of the gas broader, along the merging axis and in oppositio n to the two groups. We present the first determination of the gradients of the gas temperature and metallicity for a cluster in the Shapley region at large distance from the cluster centre. From an analysis of the BeppoSAX d ata in annuli and sectors, we observe both the profiles to be flat within 8 arcmin (similar to 0.62 Mpc), with emission-weighted values of kT = 5.1 +/ - 0.2 keV and Z = 0.39 +/- 0.05 Z.. The value of the temperature is consist ent with recent ASCA measurements and is significantly higher than previous estimates obtained from ROSAT and EXOSAT. We discuss the possible reasons for this disagreement. Between 8 and 20 arcmin, the plasma temperature decl ines to about 3.2 keV. When a polytropic profile is used to represent the g as temperature profile, the best-fitting polytropic index is 1.16 +/- 0.03. These results imply a total mass within the virial radius of 3.9(+/- 0.4) x 10(14) h(50)(-1) M., between 40 and 80 per cent lower than the optical es timate, and a gas mass fraction of about 30 per cent.