structure still describes the original tidal field. In the case of low mass haloes, the alignment seems to reverse. This result can be understood by an intuitive non-linear effect beyond the abilities of TTT, for example if these haloes have formed recently in filaments, from the merger of material arriving from voids surrounding these elongated structures.

The 1-halo term results indicate that regardless of halo mass, the structure within dark-matter haloes is preferentially aligned with the plane perpendicular to the angular momentum, with a higher statistical significance and signal than the 2-halo term.

(430,250) (-35,0) (215,0)

(350,420) (15,240) (0,0)

Simulating observational biases in the numerical simulation
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It can be difficult to estimate the angular momentum of real galaxies. In the case of the SDSS-DR6, which we use in this work, the only information that can allow us to obtain an estimate of the direction of the angular momentum is the photometry of galaxy images, specially for spiral galaxies but also for ellipticals. We assume that spiral discs or flattened spheroids are perpendicular to the angular momentum of galaxies and therefore, edge-on galaxies (either disks or spheroidals) will be more likely to have their angular momentum on the plane of 