Comastri, A.A.ComastriStirpe, G. M.G. M.StirpeVignali, C.C.VignaliFiore, F.F.Fiore2020-09-172020-09-172001-01-01https://hdl.handle.net/20.500.13025/13Astronomy and Astrophysics, v.365, p.400-408 (2001)The BeppoSAX observations of the bright Narrow-Line Seyfert 1 galaxy Ark 564 are presented along with a high quality optical spectrum taken at the 1.5 m telescope at La Silla. The 0.1-10 keV X-ray spectrum is characterized by a strong soft component which is best described by blackbody-like emission with a temperature of ~ 160 eV. At higher energies a steep (Gamma =~ 2.4) power-law tail is present. There is evidence of an ionized reflector in the form of an iron line and edge. We do not find significant evidence of soft X-ray features if the spectrum is modelled with a two component continuum. The optical and X-ray spectral properties support the hypothesis of a high accretion rate onto a low mass black hole.X-RAYS GALAXIESGALAXIES SEYFERTGALAXIES INDIVIDUAL ARK 56410.1051/0004-6361 20000152http://adsabs.harvard.edu/abs/2001A&A...365..400C2001A&A...365..400C