We present modelling of X-ray polarization spectra emerging from the two competing scenarios that are proposed to explain the broad Fe Ka line in the Seyfert 1 galaxy MCG-6-30-15. The polarization signature of complex absorption is studied for a partial covering scenario using a clumpy wind and compared to a reflection model based on the lamppost geometry. The shape of the polarization percentage and angle as a function of photon energy are found to be distinctly different between the reflection and the absorption cases. Relativistic reflection produces significantly stronger polarization in the 110 keV energy band than absorption. The spectrum of the polarization angle adds additional constraints: in the absorption case it shows a constant shape, whereas the relativistic reflection scenario typically leads to a smooth rotation of the polarization angle with photon energy. Based on this work, we conclude that a soft X-ray polarimeter onboard a small X-ray satellite may already discriminate between the absorption and the reflection scenarios. A promising opportunity may arise with the X-ray Imaging Polarimetry Explorer mission, which has been proposed to the European Space Agency in response to a small-size (S-class) mission call due for launch in 2017.

Marin, F., Goosmann, R.w., Dovciak, M., Muleri, F., Porquet, D., Grosso, N., et al. (2012). X-ray polarimetry as a new tool to discriminate reflection from absorption scenarios - predictions for MCG-6-30-15. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 426(1), L101-L105 [10.1111/j.1745-3933.2012.01335.x].

X-ray polarimetry as a new tool to discriminate reflection from absorption scenarios - predictions for MCG-6-30-15

MATT, Giorgio
2012-01-01

Abstract

We present modelling of X-ray polarization spectra emerging from the two competing scenarios that are proposed to explain the broad Fe Ka line in the Seyfert 1 galaxy MCG-6-30-15. The polarization signature of complex absorption is studied for a partial covering scenario using a clumpy wind and compared to a reflection model based on the lamppost geometry. The shape of the polarization percentage and angle as a function of photon energy are found to be distinctly different between the reflection and the absorption cases. Relativistic reflection produces significantly stronger polarization in the 110 keV energy band than absorption. The spectrum of the polarization angle adds additional constraints: in the absorption case it shows a constant shape, whereas the relativistic reflection scenario typically leads to a smooth rotation of the polarization angle with photon energy. Based on this work, we conclude that a soft X-ray polarimeter onboard a small X-ray satellite may already discriminate between the absorption and the reflection scenarios. A promising opportunity may arise with the X-ray Imaging Polarimetry Explorer mission, which has been proposed to the European Space Agency in response to a small-size (S-class) mission call due for launch in 2017.
2012
Marin, F., Goosmann, R.w., Dovciak, M., Muleri, F., Porquet, D., Grosso, N., et al. (2012). X-ray polarimetry as a new tool to discriminate reflection from absorption scenarios - predictions for MCG-6-30-15. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 426(1), L101-L105 [10.1111/j.1745-3933.2012.01335.x].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/134641
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