Spatial Orientation of Spin Vectors of Blue-shifted Galaxies

TL;DR

This study analyzes the spatial orientation of blue-shifted galaxy spin vectors using a large sample and simulations, finding mostly random orientations with some local effects, supporting the hierarchical galaxy formation model.

Contribution

It introduces a comprehensive analysis of blue-shifted galaxy orientations using simulations and statistical tests, providing evidence for random spin vector distributions.

Findings

Most blue-shifted galaxies have randomly oriented spin vectors.

No significant large-scale preferred alignment detected.

Local gravitational interactions influence galaxy orientations.

Abstract

We present the analysis of the spin vector orientation of 5$\,$987 SDSS galaxies having negative redshift from $-$87.6 to $-$0.3 km$\,$s$^{-1}$. Two dimensional observed parameters are used to compute three dimensional galaxy rotation axes by applying `position angle--inclination' method. We aim to examine the non-random effects in the spatial orientation of blue-shifted galaxies. We generate 5$\times$10$^6$ virtual galaxies to find expected isotropic distributions by performing numerical simulations. We have written MATLAB program to facilitate the simulation process and eliminate the manual errors in the process. Chi-square, auto-correlation, and the Fourier tests are used to examine non-random effects in the polar and azimuthal angle distributions of the galaxy rotation axes. In general, blue-shifted galaxies show no preferred alignments of galaxy rotation axes. Our results support Hierarchy model, which suggests a random orientation of angular momentum vectors of galaxies. However, local effects are noted suggesting gravitational tidal interaction between neighboring galaxies.