Cluster Orientation Alignments

Galaxy clusters are not spherical; they are elongated triaxial structures whose major axes show a strong tendency to align with the large-scale filaments and sheets in which they are embedded, and to align with each other over distances of tens to hundreds of megaparsecs. The orientation of a cluster's major axis, the orientation of its brightest cluster galaxy, the distribution of satellite galaxies, and the direction toward neighboring clusters all tend to point preferentially along the same large-scale filamentary axis. While ΛCDM N-body simulations do predict some degree of alignment from the tidal torque and accretion history of halos, the observed alignment signal consistently exceeds the simulated prediction, particularly on the largest scales where the observed alignment persists to separations of 100 Mpc or more — beyond the scale where tidal torque theory predicts significant correlation.

Successive Collision Theory predicts cluster orientation alignments as a direct and fundamental consequence of angular momentum inheritance, with the alignment signal naturally extending to the largest observable scales. The initial pocket collision deposited angular momentum throughout the debris field with a specific spatial coherence set by the collision geometry — the same coherence that aligns galaxy spins, radio jet axes, and the CMB quadrupole-octupole axis. Galaxy clusters formed from contiguous regions of this debris field and therefore inherited angular momentum vectors that are coherent across scales set by the collision's impact parameter geometry. The major axes of triaxial cluster halos are aligned perpendicular to their inherited angular momentum vectors, which are themselves coherent across the full collision debris volume. The alignment signal therefore does not decay with increasing separation in SCT as it does in ΛCDM tidal torque models; instead it persists to whatever scale the angular momentum coherence extends, which in SCT is set by the collision geometry rather than the limited range of tidal interactions.

The nested comoving frame hierarchy further reinforces cluster orientation alignments through the preferred infall directions established by the parent frame gravitational structure. Clusters accrete material preferentially along the filamentary axes set by the parent frame's tidal field, and since all clusters within the same supercluster-scale frame inherit their preferred accretion axis from the same parent frame angular momentum, their elongation axes are correlated at the supercluster scale. The exceptional alignment of the Perseus-Pisces, Coma-A2197, and other nearby supercluster chains along the same large-scale axis is a natural prediction of SCT's nested frame alignment mechanism — each chain lies within a common angular momentum stratum of the collision debris — rather than a statistical coincidence requiring special tidal field configurations in ΛCDM.