VLBI Structure of NGC 1275 at 3 Millimeters

Extract

We have made λ 3mm VLBI observations of 3C84 at 6 epochs between 1981 and 1987, using 6m antennas at the Hat Creek Radio Astronomy Observatory (HCRK), 10m antennas at the Owens Valley Radio Observatory (OVRO), the 12m Kitt Peak telescope (KTPK), and the 14m telescope at the Five College Radio Astronomy Observatory (QBBN). Model fitting suggests a core-halo structure, which we associate with the active nucleus of NGC 1275. The unresolved core, which is smaller than 0.1 pc (0.2 mas; z=0.018; H =50 km s⁻¹ Mpc⁻¹) shows a slow decay corresponding to the decrease in total flux density since the flare in 1980. In 1985 we resolved the core component on a transcontinental baseline (10⁹λ) into a compact nucleus, < 0.1 mas, and a “jet” extended at a position angle 205° and unresolved in width, < 0.1 mas. There is also evidence for a compact emission region located 10 mas from the nucleus at a position angle 170°. This structure corresponds closely with that observed at the same epoch in VLBI maps at 22 GHz.