Stellar Kinematics in the Cosmic Web: Lessons from the SAMI Survey and the Horizon-AGN Simulation

We reconstruct the 3D network of cosmic filaments on Mpc scales across GAMA fields and assign SAMI field galaxies to their nearest filament to estimate the degree of alignment between SAMI galaxies' kinematic axes and their nearest filament in projection. We present the first detection of differential galactic spin alignment trends with local cosmic filaments using IFS kinematics. Low-mass galaxies show a tendency to align their spin with their nearest filament while higher mass counterparts are more likely to display an orthogonal orientation. The stellar transition mass is confidently bracketed between 10^(10.1) Msun and 10^(10.7) Msun. In addition, we find that on average, v/sigma peaks at a physical distance d=2.4(+- 0.5) Mpc from the centre of the filaments. A similar trend is recovered in the Horizon-AGN simulation. We also find this trend to be consistent with the build-up of galaxies in rich vorticity quadrants dispatched around filaments identified in the Horizon-AGN simulation.