2013MNRAS.435.1287P

We present detailed broad-band X-ray spectral variability of a Seyfert 1 galaxy 1H 0419-577 based on an archival Suzaku observation in 2007 July, a new Suzaku observation performed in 2010 January and the two latest XMM-Newton observations from 2010 May. All the observations show soft X-ray excess emission below 2keV and both Suzaku observations show a hard X-ray excess emission above 10keV when compared to a power law. We have tested three physical models - a complex partial covering absorption model, a blurred reflection model and an intrinsic disc Comptonization model. Among these three models, the blurred reflection model provided statistically the best fit to all the four observations. Irrespective of the models used, the soft X-ray excess emission requires contribution from a thermal component similar to that expected from an accretion disc. The partial covering absorption model results in a non-physical high temperature (kTin ∼ 100eV) for an accretion disc and is also statistically the worst fit among the three models. 1H 0419-577 showed remarkable X-ray spectral variability. The soft X-ray excess and the power law both became weaker in 2010 January as well as in 2010 May. A moderately broad iron line, detected in 2007 July, is absent in the 2010 January observation. Correlated variability of the soft X-ray excess and the iron Kα line strongly suggest reflection origin for both the components. However, such spectral variability cannot be explained by the light bending model alone and requires changes in the accretion disc/corona geometry possibly arising from changes in the accretion rate.