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| - XMM-Newton broad-band observations of NGC 7582: N$_{\mathsf{H}}$ variations and fading out of the active nucleus
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| - We present results from two XMM-Newton observations of the bright classical Seyfert 2 galaxy NGC 7582 taken four years apart (2001 May and 2005 April). We present the analysis of the high-resolution (0.3-1 keV) RGS and low-resolution (0.3-10 keV) EPIC spectroscopic data.
A comparison with a 1998 BeppoSAX observation suggests that XMM-Newton caught the source in a “reflection-dominated” phase, measuring the lowest continuum flux level ever ( F2-10 = 2.3 $\times$ 10 -12 erg cm -2 s -1) in 2005. NGC 7582 therefore experienced a dramatic spectral transition most likely due to the partial switching-off of the nuclear activity. The XMM-Newton spectrum of the continuum emission is very complex. It can be well described by a model consisting of a combination of a heavily absorbed ( NH ~ 10 24 cm -2) power law and a pure reflection component both obscured by a column density of ~ $4 \times 10^{22}$ cm -2. Notably, we detect a significant increase by a factor of ~2 in the column density of the inner, thicker absorber covering the primary X-ray source between 2001 and 2005. The 2005 XMM-Newton spectrum shows the strongest Fe K α emission line ever measured in this source. This is consistent with the line delayed time response to the decrease of the nuclear activity. Our analysis also reveals that the soft X-ray spectrum is dominated by emission lines from highly ionized metals. The detection of a narrow OVIII radiative recombination continuum suggests an origin in a photoionized plasma.
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