Speaker
Description
In this paper, we apply the two-component model of γ-ray emission to examine the consistency of the unified scheme of Fanaroff–Riley Type II radio galaxies (FR-IIs) and Flat-Spectrum Radio Quasars (FSRQs) based on the combined data of 220 FSRQs and 46 FR IIs from Fourth Fermi Large Area Telescope (Fermi-LAT) catalogue and 107 Non-Fermi detected FR IIs. Based on the relativistic beaming concept, we derive the γ-ray core-dominance and used the γ-ray beaming factor to estimate the beamed and unbeamed γ-ray emissions. Our main results are as follows: (1) The γ-ray core-dominance (in logarithmic scale) for Fermi-detected FR-IIs ranges from -1.23 to 2.19, and for non-Fermi-detected FR-IIs, from -1.08 to 1.15. For FSRQs, it ranges from -2.5 to 6.78. On average, FR-IIs have lower γ-ray core-dominance than FSRQs, supporting the unified model that FR-IIs are misaligned FSRQs with lower core-dominance. (2) γ-ray emission in FSRQs is primarily core-dominated and is about a thousand times stronger than that from their extended regions. A strong correlation between γ-ray core-dominance and the corresponding radio emission suggests that γ-ray emission is significantly influenced by beaming effects. (3) We propose that different regions of FR-IIs in the plot of the γ-ray luminosity against the radio core-dominance may indicate the different beaming effects. These results confirm that FSRQ γ-ray emission mainly comes from the beamed component and support the orientation-based unified model linking FR-IIs and FSRQs
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