The velocity shear tensor: tracer of halo alignment

Understand

The alignment of DM halos and the surrounding large scale structure (LSS) is examined in the context of the cosmic web.

• Halo spin, shape and the orbital angular momentum of subhaloes is investigated relative to the LSS using the eigenvectors of the velocity shear tensor evaluated on a grid with a scale of 1 Mpc/h, deep within the non-linear regime.
• Knots, filaments, sheets and voids are associated with regions that are collapsing along 3, 2, 1 or 0 principal directions simultaneously.
• Each halo is tagged with a web classification (i.e.