Snapshots of a simulation of a relativistic, electron-positron jet propagating through a dilute ambient medium, as expected to be the case for the re-started jet in 3C 84. The left panel shows a 3D render of the leptonic mass fraction (which identifies the jet), three temperature contours (2.5 × 10⁸ K in faint yellow, 2.1 × 10¹⁰ K in faint blue and 1.8 × 10¹² K in dark blue), and atomic hydrogen density (brown clumps). The right panel shows a 3D render of the leptonic mass fraction and a pressure contour (faint yellow), to show the position of the jet bow shock. The plots were produced with LLNL VisIt software (Childs 2012).