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arXiv · 1710.08098

The Hard X-ray emission of the blazar PKS 2155--304

Haritma Gaur·Liang Chen·R. Misra·S. Sahayanathan·M. F. Gu·P. Kushwaha·G. C. Dewangan
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Abstract

The synchrotron peak of the X-ray bright High Energy Peaked Blazar (HBL) PKS 2155$-$304 occurs in the UV-EUV region and hence its X-ray emission (0.6--10 keV) lies mostly in the falling part of the synchrotron hump. We aim to study the X-ray emission of PKS 2155$-$304 during different intensity states in 2009$-$2014 using XMM$-$Newton satellite. We studied the spectral curvature of all of the observations to provide crucial information on the energy distribution of the non-thermal particles. Most of the observations show curvature or deviation from a single power-law and can be well modeled by a log parabola model. In some of the observations, we find spectral flattening after 6 keV. In order to find the possible origin of the X-ray excess, we built the Multi-band Spectral Energy distribution (SED). We find that the X-ray excess in PKS 2155--304 is difficult to fit in the one zone model but, could be easily reconciled in the spine/layer jet structure. The hard X-ray excess can be explained by the inverse Comptonization of the synchrotron photons (from the layer) by the spine electrons.

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Haritma Gaur, Liang Chen, R. Misra, S. Sahayanathan, M. F. Gu, P. Kushwaha, G. C. Dewangan. 2017-10-23. The Hard X-ray emission of the blazar PKS 2155--304. https://doi.org/10.3847/1538-4357/aa95bc

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