A Possible Large-scale Alignment of Galaxy Spin Directions -- Analysis of 10 Datasets from SDSS, Pan-STARRS, and HST

TL;DR

This study analyzes ten large galaxy datasets from SDSS, Pan-STARRS, and HST, revealing a redshift-dependent shift in the preferred axis of galaxy spin directions, suggesting possible large-scale cosmic anisotropy.

Contribution

It provides the first comprehensive comparison of multiple datasets showing a redshift-dependent alignment of galaxy spin axes, indicating potential cosmological-scale structures.

Findings

Most probable dipole axes are consistent within similar redshift groups.

The axis location shifts with increasing redshift, indicating a possible cosmological drift.

The shift is statistically significant, supporting the hypothesis of large-scale anisotropy.

Abstract

Multiple observations made by several different telescopes have shown asymmetry between the number of spiral galaxies rotating in opposite directions in different parts of the sky. One of the immediate questions regarding the possible asymmetry of the spin directions is whether the distribution forms a cosmological-scale axis. This paper analyzes and compares 10 different datasets published in the past decade, collected by SDSS, Pan-STARRS, and Hubble Space Telescope. The datasets contain spiral galaxies separated by their spin direction, and the distribution can show dipole axes. The analysis shows that the directions of the most probable dipole axes are consistent in datasets that have similar average redshift, but different between datasets that have different average redshift. The analysis also shows that the location of the most probable axis correlates with the average redshift of the galaxies in the datasets. That is, the location of the most probable axis shifts when the redshift gets higher, and the correlation is statistically significant. This provides a certain indication of a drift in a possible axis formed by the distribution of galaxy spin directions, or a cosmological scale structure that peaks at a certain distance from Earth.