BeppoSAX observations of Mrk 509 and MCG+8-11-11

BeppoSAX observations of the Seyfert galaxies Mrk 509 and MCG +8-11-11 are presented. Earlier evidence of a soft excess in Mrk 509 is confirmed. This excess is found to be better represented by a power law than by a black bod y: with a photon slope Gamma(S) of 2.5, its extrapolation matches the flux recorded in the far UV. An ASCA observation, which appeared to exclude the presence of the excess while showing instead evidence of a warm absorber, t urns out to be compatible with the coexistence of the excess seen with Bepp oSAX and of the warm absorber. The hard power law of Mrk 509 is seen for th e first time to be affected by a cut-off at high energies, with an e-foldin g energy of about 70 keV. Tn MCG +8-11-11 the cut-off is found at about 170 keV, consistent within the combined errors with a previous estimate from a ASCA+OSSE/CGRO observation. In both objects the reflection component is cl early detected. In Mrk 509 its strength, together with that of the iron K l ine, indicates a solid angle Omega, subtended by the reprocessing gas in th e accretion disk, much less than 2 pi, but lacking a valid constraint on th e inclination angle this evidence is not as convincing as that found with B eppoSAX in TC 4329A. In MCG +8-11-11 the same parameters are instead consis tent with Omega=2 pi, but the comparison with an ASCA observation, when the flux level was about 2.5 times weaker, suggests that a substantial fractio n of the angle might be associated with gas farther out than the accretion disk.