KVN observations reveal multiple γ-ray emission regions in 3C 84?

Abstract

3C 84 (NGC 1275) is a well-studied misaligned sctive galactic nucleus (AGN), which has been active in gamma-rays since at least 2008. We have monitored the source at four wavelengths (14, 7, 3, and 2mm) using the Korean VLBI network (KVN) since 2013 as part of the interferometric monitoring of gamma-ray bright AGN (iMOGABA) programme, and it exhibits bright radio emission both near the central SMBH and in a slowly moving feature located to the south known as C3. Other facilities have also detected these short-term variations above a slowly rising trend at shorter wavelengths, such as in gamma-ray and 1-mm total intensity light curves. We find that the variations in the gamma-rays and 1-mm total intensity light curves are correlated, with the gamma-ray leading and lagging the radio emission. Analysis of the 2-mm KVN data shows that both the gamma-rays and 1-mm total intensity short-term variations are better correlated with the SMBH region than C3, likely placing the short-term variations in Cl. We interpret the emission as being due to the random alignment of spatially separated emission regions. We place the slowly rising trend in C3, consistent with previous results. Spectral analysis of the gamma-ray data shows that the gamma-ray flaring is inconsistent with blazar-like gamma-ray emission. Additionally, we report that since mid-2015, a large mm-wave radio flare has been occurring in C3, with a large gamma-ray flare coincident with the onset of this flare at all radio wavelengths.