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arXiv · 2404.12835

Distinguishing radiation mechanisms and particle populations in blazar jets through long-term multi-band monitoring with RINGO3 and Fermi

Callum McCall·Helen Jermak·Iain A. Steele·Iván Agudo·Ulisses Barres de Almeida·Talvikki Hovatta·Gavin P. Lamb·Elina Lindfors·Carole Mundell
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Abstract

We present the results of seven years of multicolour photometric monitoring of a sample of 31 $\gamma$-ray bright blazars using the RINGO3 polarimeter on the Liverpool Telescope from 2013--2020. We explore the relationships between simultaneous observations of flux in three optical wavebands along with Fermi $\gamma$-ray data in order to explore the radiation mechanisms and particle populations in blazar jets. We find significant correlations between optical and $\gamma$-ray flux with no detectable time lag, suggesting leptonic emission processes in the jets of these sources. Furthermore, we find the spectral behaviour against optical and $\gamma$-ray flux for many sources is best fit logarithmically. This is suggestive of a transition between bluer-/redder-when-brighter into stable-when-brighter behaviour during high activity states; a behaviour that might be missed in poorly sampled data, resulting in apparent linear relationships.

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Callum McCall, Helen Jermak, Iain A. Steele, Iván Agudo, Ulisses Barres de Almeida, Talvikki Hovatta, Gavin P. Lamb, Elina Lindfors, Carole Mundell. 2024-04-19. Distinguishing radiation mechanisms and particle populations in blazar jets through long-term multi-band monitoring with RINGO3 and Fermi. https://doi.org/10.1093/mnras%2Fstae1693

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