EDP Sciences
Free access
Issue
A&A
Volume 373, Number 3, July III 2001
Page(s) 805 - 815
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20010582


A&A 373, 805-815 (2001)
DOI: 10.1051/0004-6361:20010582

XMM-Newton observation of the Seyfert 1 galaxy Fairall 9

P. Gondoin1, D. Lumb1, H. Siddiqui1, M. Guainazzi2 and N. Schartel2

1  Astrophysics Division, European Space Agency -Postbus 299, 2200 AG Noordwijk, The Netherlands
2  ESA Villafranca Satellite Tracking Station, Apartado 50727, 28080 Madrid, Spain

(Received 20 February 2001 / Accepted 19 April 2001 )

Abstract
We report an X-ray observation of the Fairall 9 Seyfert 1 galaxy performed in July 2000 with the EPIC cameras and Reflection Grating Spectrometers (RGS) on board the XMM-Newton observatory. Above 2 keV, the high signal to noise ratio of the EPIC spectra shows an emission line at $6.38\pm0.03$ keV with a measured equivalent width of 120 eV. An absorption edge is also detected at 7.64+0.21-0.36 in the source rest frame that has not been reported before. Spectral fitting of the measured spectra with reflection models indicates that these imprinted features are likely the result of partial reprocessing of a primary X-ray continuum by optically thick material. The positions in energy of the emission line and absorption edge are consistent with Compton reflection models from material containing iron in states of ionization lower than FeXVII. The Fe K emission line is narrow suggesting that the reflection process arises from material relatively far from a putative central black hole. The best fit models show that the reflected spectrum mask a steeper intrinsic power law slope even at energies lower than 5 keV. The extrapolation of this primary continuum to energies lower than 2 keV reveals the presence of a soft excess component contributing to $14\pm6\%$ of the overall flux in the 0.3-1.0 keV energy range. No evidence is found for a warm absorber in this low energy part of the spectrum. The analysis results are discussed within the frame of recent accretion disc models in which X-rays from the primary continuum source heat up the upper layers of the disc thus creating very hot, optically thin plasmas on top of cooler denser material.


Key words: galaxies: individual: Fairall 9 -- galaxies: nuclei -- galaxies: Seyfert

Offprint request: P. Gondoin, pgondoin@estsa2.estec.esa.nl

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