GMVA21B-078

Is shear acceleration at work in the jets of NGC 315?

Abstract

AGN jets are highly efficient particle accelerators. They produce large amounts of high energy photons and energetic particles like neutrinos and cosmic rays. It has been proposed that efficient particle acceleration can take place at the boundary of the jets owing to the interaction with the surroundings through the so-called "shear acceleration" mechanism. There is indeed some observational evidence for shear acceleration in AGN jets on kiloparsec scales. However, no clear evidence has been found on parsec scales, where a good fraction of the observed high energy AGN emission is believed to be produced. One of the predictions of the shear acceleration model is limb brightening of the jets. Although there are many nearby AGN jets showing limb brightening on parsec scales, alternative scenarios using a transverse jet velocity gradient can also explain the limb brightening. Here we propose a GMVA+ALMA observation of NGC 315 to test the shear acceleration model. We aim at detecting limb brightening of its jets at a very short distance from the jet base, which cannot be explained by the alternative scenarios. The extremely high angular resolution and sensitivity provided by ALMA will provide new insight into the particle acceleration process in AGN jets.

Investigators

Name	Institution
GBT Operator	Green Bank Observatory
Laurent Loinard	México, Universidad Nacional Autónoma de
Guangyao Zhao	Max-Planck-Institut für Radioastronomie; Korea Astronomy and Space Science Institute; Andalucía, Instituto de Astrofísica de
Motoki Kino	National Astronomical Observatory of Japan ; Korea Astronomy and Space Science Institute
Keiichi Asada	Academia Sinica
Hung-Yi Pu	Perimeter Institute for Theoretical Physics
Masanori Nakamura	Academia Sinica; National Institute of Technology, Hachinohe College
Kazuhiro Hada	Istituto Nazionale di Astrofisica; National Astronomical Observatory of Japan
Jongho Park *	Kyung Hee University

* indicates the PI