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Mkn 1239: A highly polarized NLS1 with a steep X-ray spectrum and strong NeIX emission

D. Grupe·S. Mathur·S. Komossa
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Abstract

We report the results of an XMM-Newton observation of the Narrow-Line Seyfert 1 galaxy Mkn 1239. This optically highly polarized AGN has one of the steepest X-ray spectra found in AGN with alpha-X = +3.0 based on ROSAT PSPC data. The XMM-Newton EPIC PN and MOS data confirm this steep X-ray spectrum. The PN data are best-fit by a powerlaw with a partial covering absorption model suggesting two light paths between the continuum source and the observer, one indirect scattered one which is less absorbed and a highly absorbed direct light path. This result agrees with the wavelength dependent degree of polarization in the optical/UV band. Residuals in the X-ray spectra of all three XMM-Newton EPIC detectors around 0.9 keV suggest the presence of an emission line feature, most likely the Ne IX triplet. The detection of NeIX and the non-detection of OVII/OVIII suggest a super-solar Ne/O ratio.

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D. Grupe, S. Mathur, S. Komossa. 2004-02-11. Mkn 1239: A highly polarized NLS1 with a steep X-ray spectrum and strong NeIX emission. https://doi.org/10.1086/421002

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