2-6 September 2024
CJD Bonn Castell
Europe/Berlin timezone
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Contribution

Accretion mode and γ-ray emission: A comparison between 3C111 and 3C371

Speakers

  • Vieri BARTOLINI

Primary authors

Co-authors

Content

Active Galactic Nuclei (AGN) form the most abundant class of γ-ray sources. Due to Doppler boosting, the vast majority of these consist of Blazars (viewing angle θ < 8° − 10°), while misaligned (MAGN) sources (θ > 8°−10°) account for a few percent of γ-ray-detected AGN. Despite their low abundance in the γ-ray sky, MAGN are a fundamental tool to study relativistic jets, precisely because of their larger θ that allows us to better resolve the jet structure on compact scales. Based on the efficiency of the accretion onto the SMBH, AGN can be divided into two classes: High Excitation Galaxies (HEG), with a radiatively efficient accretion, and Low Excitation Galaxies (LEG) with an inefficient one. In this work, we investigate the differences between these two types of objects in the γ-ray domain, with the help of Very Long Base-line Interferometry (VLBI) and multi-wavelength observations. As case studies, we select two MAGN: one HEG (3C111) and one LEG (3C371) with similar BH masses, redshifts, jet powers, and viewing angles. We analyze overall around 200 VLBI maps, spanning over 4 years at 3 frequencies (15 GHz, 22 GHz, and 43 GHz), to investigate the relation between the structural changes observed in the radio jet and the emission at higher energies. We find substantial differences between the two sources both in the kinematics and in the γ-ray activity. 3C111 shows mostly superluminal knots, while 3C371 is dominated by stationary components, presenting a single moving feature possibly ejected after a major optical flare. Concerning the γ-ray emission, 3C111 is undetected for most of the period analyzed and shows strong flaring activity related to superluminal features emerging at the jet base, while 3C371 has a less variable light curve with few small flares. In this talk, we discuss a possible scenario that links together the accretion mode, the kinematics, and the γ-ray activity. This will be further explored with the use of 2D RMHD simulations.