HI projected column density of the jellyfish galaxy (left panel), where the cross marks the galaxy centre, and the blue triangle and black circle mark R_HI determined with a fit and by identifying the furthest upstream location with ⟨N_HI⟩≥10^20.5 cm⁻², respectively. In the right panel, we plot ⟨N_HI⟩ (see text for details) and mark R_HI determined with the different methods. At this early time of t = 2.0 Gyr, there are CGM clumps upstream from the galaxy, so we use a fit to determine the R_HI for the disc.