Large-scale asymmetry in galaxy spin directions -- analysis of galaxies with spectra in DES, SDSS, and DESI Legacy Survey

TL;DR

This study analyzes the distribution of galaxy spin directions across over 90,000 galaxies with spectra, providing evidence for large-scale anisotropy and comparing results across multiple surveys and telescopes.

Contribution

It offers a comprehensive analysis of galaxy spin directions with spectra, confirming anisotropy and consistency across different observational datasets.

Findings

Consistent distribution patterns across multiple surveys.

Evidence supporting cosmological-scale anisotropy.

Axes of galaxy spin directions do not align with Earth.

Abstract

Multiple previous studies using several different probes have shown considerable evidence for the existence of cosmological-scale anisotropy and a Hubble-scale axis. One of the probes that show such evidence is the distribution of the directions toward which galaxies spin. The advantage of the analysis of the distribution of galaxy spin directions compared to the CMB anisotropy is that the ratio of galaxy spin directions is a relative measurement, and therefore less sensitive to background contamination such as Milky Way obstruction. Another advantage is that many spiral galaxies have spectra, and therefore allow to analyze the location of such axis relative to Earth. This paper shows an analysis of the distribution of the spin directions of over 90K galaxies with spectra. That analysis is also compared to previous analyses using the Earth-based SDSS, Pan-STARRS, and DESI Legacy Survey, as well as space-based data collected by HST. The results show very good agreement between the distribution patterns observed with the different telescopes. The dipole or quadrupole axes formed by the spin directions of the galaxies with spectra do not necessarily go directly through Earth.