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The impact of thermal gas in AGN jets on the low-frequency emission

M. Siewert·M. Pohl·R. Schlickeiser
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Abstract

We study the effect of non-relativistic, thermal matter in the jets of active galaxies (AGN) on the low-frequency non-thermal emission and the variability thereof. In matter-dominated jets, sizable quantities of gas should exist, in particular in the compression zones near the collision fronts that are an implicit ingredient of Fermi-type particle acceleration scenarios. Non-relativistic thermal gas in AGN jets noticably contributes to the optical depth at radio to infrared frequencies, and much less to the emission, with an efficiency that is strongly temperature-dependent. The observable flux of low-frequency emission is thus modulated by the temperature evolution of the thermal gas, and it can therefore display very complicated variability. For a particular particle energisation scenario we calculate the temperature evolution of the thermal plasma as well as the radiation transport of low-frequency emission, and thus derive simulated light curves at different frequencies and their typical correlation properties.

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M. Siewert, M. Pohl, R. Schlickeiser. 2004-09-03. The impact of thermal gas in AGN jets on the low-frequency emission. https://doi.org/10.1051/0004-6361%3A20040546

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