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arXiv · 1004.1418

On the Spectral Break in the Fermi-LAT Spectrum of 3C 454.3

Justin D. Finke·Charles D. Dermer
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Abstract

Fermi Gamma ray Space Telescope observations of the flat spectrum radio quasar 3C~454.3 show a spectral-index change $ΔΓ\cong 1.2\pm 0.3$ at break energy $E_{br} \approx 2.4\pm0.3$ GeV. Such a sharp break is inconsistent with a cooling electron distribution and is poorly fit with a synchrotron self-Compton model. We show that a combination of two components, namely the Compton-scattered disk and broad-line region (BLR) radiations, explains this spectral break and gives a good fit to the quasi-simultaneous radio, optical/UV, X-ray, and $γ$-ray spectral energy distribution observed in 2008 August. A sharp break can be produced independent of the emitting region's distance from the central black hole if the BLR has a gradient in density $\propto R^{-2}$, consistent with a wind model for the BLR.

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Justin D. Finke, Charles D. Dermer. 2010-04-08. On the Spectral Break in the Fermi-LAT Spectrum of 3C 454.3. https://doi.org/10.1088/2041-8205%2F714%2F2%2Fl303

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