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High energy properties of the flat spectrum radio quasar 4C 50.11

Zhou, Jianeng and Jithesh, V. and Liang, Chen and Wang, Zhongxiang (2016) High energy properties of the flat spectrum radio quasar 4C 50.11. .

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We investigate the gamma-ray and X-ray properties of the flat spectrum radio quasar (FSRQ) \4c50 at redshift z= 1.517. The Fermi Large Area Telescope (LAT) data indicate that this source was in an active state since 2013 July. During the active period, the gamma-ray flux increased by more than a factor of three and two distinct flares were detected with the variability timescale as short as several hours. The gamma-ray spectra can be well fitted by a log-parabola. From the fitting, we find a correlation between the peak energy and spectral curvature for the gamma-ray spectra, which is the first time seen in gamma-ray emission from a blazar. The Swift X-ray Telescope (XRT) data show that the source was variable at X-ray energies, but no evidence shows flux or spectral changes related to the gamma-ray activity. The broad-band X-ray spectrum obtained with Swift XRT and NuSTAR is well described by a broken PL model, with an extremely hard spectrum (Γ_1 ~ 0.1) below the break energy, E_(break) ~ 2.1 keV, and Γ_2 ~ 1.5 above the break energy. The spectral steepening below ~ 3 keV is likely due to the low energy cut-off in the energy distribution of the photon-emitting electron population. Both the gamma-ray and X-ray emission appear harder when brighter. The broad-band spectral energy distribution (SED) is constructed for the source, and we provide a model fit to the SED. Our modeling suggests that the emission region should be outside the broad line region, and the properties of the region indicate a jet with 42% of the Eddington power during the active state.

Item Type:Report or Paper (Discussion Paper)
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Record Number:CaltechAUTHORS:20161004-083304078
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:70788
Deposited By: Joy Painter
Deposited On:04 Oct 2016 18:50
Last Modified:03 Oct 2019 16:01

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