2010A&A...514A..58I

We present a Suzaku observation of the dwarf Seyfert galaxy NGC 4395 with an estimated black hole mass of ∼10⁵M_☉. Rapid and strong X-ray variability with an rms amplitude of ∼60 per cent is observed in the 0.4-10keV band with the XIS cameras. The shape of the light curve appears to depend on energies. The hard X-ray emission is detected up to 35keV with the HXD-PIN detector at a similar flux level as observed with the INTEGRAL IBIS. The X-ray spectrum below 10keV is strongly absorbed by partially ionized (xsi∼35erg.s/cm) gas with a mean equivalent hydrogen column density of ∼2x10²²cm^–2, when a simple absorption model is applied. The spectral shape is also strongly variable but not a simple function of the source brightness. The spectral variability appears to be accounted for mainly by continuum slope changes, but variability in the ionized absorber may also play some part. The apparently flat spectral slope of Γ≃1.4 below 10keV, obtained after correcting for absorption, is marginally inconsistent with the Γ∼2 inferred from the 14-35keV PIN spectrum. If the true spectral slope had been as steep as that measured in the hard X-ray band, there would have been an extra absorption component, which we are unable to detect. Combined with the INTEGRAL measurements, the hard X-ray emission above 10keV exceeds the optical emission in terms of luminosity and dominates the broadband energy output, unless a large excess of UV disk emission is yet to be detected in the unobservable band. A weak Fe K line is seen at 6.4keV with the average equivalent width of 110eV, which does not show significant flux changes over the 3-day observation.