Large‐scale asymmetry between clockwise and counterclockwise galaxies revisited

Abstract

The ability of digital sky surveys to collect and store very large amounts of data provides completely new ways to study the local universe. Perhaps one of the most provocative observations reported with such tools is the asymmetry between galaxies with clockwise and counterclockwise spin patterns. Here I use ∼ 1.7 · 10 5 spiral galaxies from SDSS and sort them by their spin patterns (clockwise or counterclockwise) to identify and profile a possible largescale pattern of the distribution of galaxy spin patterns as observed from Earth. The analysis shows asymmetry between the number of clockwise and counterclockwise spiral galaxies imaged by SDSS, and a dipole axis. These findings largely agree with previous reports using smaller datasets. The probability of the differences between the number of galaxies to occur by chance is (P < 4 · 10 −9 ), and the probability of an asymmetry axis to occur by mere chance is (P < 1.4 · 10 −5 ).

Spin Parity of Spiral Galaxies III -- Dipole Analysis of the Distribution of SDSS Spirals with 3D Random Walk Simulations

“…The original sample shows an S/Z dipole signal of D max = 0.00489, with its axis pointing toward (l, b) = (189 • , +15 • ). This axis coincides with that reported in Shamir (2020a), (α = 88 • , δ = +36 • ), which is (l = 175 • , b = +5 • ) for an SDSS sample, considering the 1σ estimation error of about 30 • in both coordinates.…”

“…The D max value observed for this sample, together with that of 50,000 simulated mock samples is shown in Figure 3. The observed D max from the original catalog limited to a volume defined by redshift, therefore, has an amplitude, that is larger than the mean amplitude by σ D = 4.00.This amplitude happens to be close to the value 4.34σ reported in Shamir (2020a). The number dominance for this sample is 6.36σ.…”

Multipole alignment in the large-scale distribution of spin direction of spiral galaxies

“…Data from two different digital sky surveys were used in this experiment, to allow a comparison be-tween data collected by different telescopes and reduce the probability that the results are driven by an unknown instrumental flaw in a certain telescope system. The first dataset is ∼ 1.7 • 10 5 spiral galaxies from SDSS annotated by their spin directions, and it is the same dataset used in [39,41,40,43]. The galaxies are spiral galaxies taken from the catalog of ∼ 3 • 10 6 SDSS galaxies classified automatically into spiral and elliptical galaxies [21].…”

“…The ability to automate the galaxy annotation led to far larger datasets, that are less vulnerable to human bias due to the machine-based nature of the annotation. Automatically annotated datasets of galaxy images showed clear and statistically significant asymmetry between clockwise and counterclockwise galaxies in Sloan Digital Sky Survey [39,41,43]. While the first experiments were based on SDSS alone, more recent work using several telescopes showed very good agreement between SDSS and data collected by other telescopes such as Pan-STARRS [40], and Hubble Space Telescope [42].…”

“…Because the spin direction of a spiral galaxy depends on the perspective of the observer, the distribution of the spin directions of spiral galaxies is expected to be randomly distributed in the sky to an Earth-based observer. However, several previous studies showed evidence of non-random patterns of the distribution of spin directions of spiral galaxies [25,36,37,15,38,39,41,40,23,24,42,43].…”