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Exploring the complex X-ray spectrum of NGC 4051

K. A. Pounds·J. N. Reeves·A. R. King·K. L. Page
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Abstract

Archival XMM-Newton data on the nearby Seyfert galaxy NGC 4051, taken in relatively high and low flux states, offer a unique opportunity to explore the complexity of its X-ray spectrum. We find the hard X-ray band to be significantly affected by reflection from cold matter, which can also explain a non-varying, narrow Fe K fluorescent line. We interpret major differences between the high and low flux hard X-ray spectra in terms of the varying ionisation (opacity) of a substantial column of outflowing gas. An emission line spectrum in the low flux state indicates an extended region of photoionised gas. A high velocity, highly ionised outflow seen in the high state spectrum can replenish the gas in the extended emission region over ~10^3 years, while having sufficient kinetic energy to contribute significantly to the hard X-ray continuum.

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K. A. Pounds, J. N. Reeves, A. R. King, K. L. Page. 2004-01-16. Exploring the complex X-ray spectrum of NGC 4051. https://doi.org/10.1111/j.1365-2966.2004.07639.x

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