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 (\ensuremathα_ ox∼2.0) during our observations. Compiling values of \ensuremathα_ ox from a larger NLS1s, we find that, although the sample is small, the \ensuremathα_ ox distribution suggests that X-ray weakness may occur more frequently among more luminous NLS1s.
URL : http://ptp.ipap.jp/link?PTPS/155/377/
DOI : 10.1143/PTPS.155.377