XMM-NewtonObservations of Luminous Narrow-Line Seyfert 1 Galaxies

We observed four optically-luminous narrow-line Seyfert 1 galaxies (NLS1s) with XMM-Newton. All the four NLS1s were detected. The observed X-ray spectra were rather steep (Γ = 2-3), as is typical among NLS1s. Utilizing simultaneous UV observations by the XMM-Newton optical monitor (OM), we also investigate the spectral energy distributions in the UV-X-ray band. One object (RX J1225.7+2055) of the four was found to be X-ray weak (α o x ∼2.0) during our observations. Compiling values of α O X from a larger NLS1s, we find that, although the sample is small, the α O X distribution suggests that X-ray weakness may occur more frequently among more luminous NLS1s.