The enigmatic soft X-ray AGN RX J0134.2-4258

We report the discovery and analysis of the followup ROSAT pointed observat ion, an ASCA observation and optical and radio observations of the enigmati c soft X-ray AGN RX J0134.2-4258. In the optical, RX J0134.2-4258 appears a s an extreme 'Narrow-Line Seyfert 1 galaxy' (NLS1), with very strong Fell e mission, very blue optical continuum spectrum and almost no Narrow Line Reg ion emission. While its spectrum was one of the softest observed From an AG N during the ROSAT All-Sky Survey, its spectrum was found to be dramaticall y harder during a pointed observation although the count rate remained cons tant. We found in the pointed observation that the spectrum is softer when it is fainter and spectral fitting demonstrates that it is the hard compone nt that is variable. The ASCA observation confirms the presence of a hard X -ray power law, the slope of which is rattler flat compared with other NLS1 s. Survey and followup radio observations reveal that RX J0134.2-4258 is al so unusual in that it is a member of the rare class of radio-loud NLS Is, a nd, with R=71, it holds the current record for largest radio-to-optical rat io in NLS1s. We discuss possible scenarios to explain its strange behaviour .