GENJI Programme: Gamma-ray Emitting Notable AGN Monitoring by Japanese VLBI

TL;DR

The GENJI program uses Japanese VLBI to monitor gamma-ray bright AGNs, aiming to understand radio jet dynamics and their relation to gamma-ray emissions through dense, short-timescale observations.

Contribution

This study introduces the GENJI program, a novel VLBI monitoring initiative that provides high-cadence radio observations of gamma-ray AGNs, enabling detailed analysis of jet activity and multi-wavelength correlations.

Findings

Successful coordination of rapid follow-up observations after gamma-ray flares.

Initial morphology and light curve data obtained over 7 months.

Potential to trace short-term radio variability and jet ejections.

Abstract

We introduce the GENJI program (Gamma-ray Emitting Notable AGN Monitoring by Japanese VLBI), which is a monitoring program of gamma-ray bright AGNs with the VERA array (VLBI Exploration of Radio Astrometry). The GENJI programme aims a dense monitoring at 22 GHz towards the $\gamma$-ray emitting active galactic nuclei (AGNs) to investigate the radio time variation of the core and possible ejection of new radio component, motion of jets, and their relation with the emission at other wavelengths especially in $\gamma$-rays. Currently we are monitoring 8 $\gamma$-ray-emitting notable AGNs (DA 55, 3C 84, M 87, PKS 1510-089, DA 406, NRAO 530, BL Lac, 3C 454.3) about once every two weeks. This programme is promising to trace the trend of radio time variation on shorter timescale than conventional VLBI monitoring programme and to provide complimentary data with them (e.g., MOJAVE, Boston University Blazar Project). In particular, we successfully coordinated quick follow-up observations after the GeV $\gamma$-ray flare in NRAO 530 and 3C 454.3 reported by the Fermi Gamma-ray Space Telescope. Here we present the initial results of morphology and light curves for the first 7-month operation.