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We report the discovery of RX J2317.8-4422 in an extremely low X-ray fluxstate by the Neil Gehrels Swift observatory in 2014 April/May. In total, thelow-energy X-ray emission dropped by a factor 100. We have carried outmulti-wavelength follow-up observations of this Narrow-Line Seyfert 1 galaxy.Here we present observations with Swift, XMM-Newton, and NuSTAR in October andNovember 2014 and further monitoring observations by Swift from 2015 to 2018.Compared with the beginning of the Swift observations in 2005, in the November2014 XMM and NuSTAR observation RX J2317--4422.8 dropped by a factor of about80 in the 0.3-10 keV band. While the high-state Swift observations can beinterpreted by a partial covering absorption model with a moderate absorptioncolumn density of $N_H=5.4\times 10^{22}$ cm$^{-2}$ or blurred reflection, dueto dominating background at energies above 2 keV the low-state XMM data can notdistinguish between different multi-component models and were adequately fitwith a single power-law model.  We discuss various scenarios like a long-term change of the accretion rate orabsorption as the cause for the strong variability seen in RX J2317.8--4422.

Swift, NuStar and XMM-Newton observations of the NLS1 galaxy RX J2317.8-4422 in an extreme X-ray low flux state