Pinpointing the jet apex of 3C 84

Nearby radio galaxies that contain jets are extensively studied with VLBI, addressing jet launching and the physical mechanisms at play around massive black holes. 3C 84 is unique in this regard, because combination of its proximity large SMBH mass provides a high spatial resolution to resolve complex structure base. For an angular scale 50 ${\mu}$as corresponds 200 - 250 Schwarzschild radii ($R_s$). Recent RadioAstron VLBI imaging 22 GHz revealed east-west elongated feature northern end jet, which challenges interpretations. Here we propose instead apex not located within core region but more upstream jet. We base our arguments on 2D cross-correlation analysis quasi-simultaneously obtained images 15, 43, 86 GHz, measures opacity shift 84. With assumption power law index ($k_r$) being set 1, find be $83 \pm 7$ north (upstream) core. Depending assumptions for $k_r$ particle number density n, mixed toroidal/poloidal magnetic field configuration, consistent offset from central engine by about 400-1500 $R_s$. The measured then used estimate strength, amounts B = 1.80 4.0 G near discuss some implications these findings.