Patterns of galaxy spin directions in SDSS and Pan-STARRS show parity violation and multipoles. (arXiv:2007.16116v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Shamir_L/0/1/0/all/0/1">Lior Shamir</a>
The distribution of spin directions of $sim6.4cdot10^4$ SDSS spiral
galaxies with spectra was examined, and compared to the distribution of
$sim3.3cdot10^4$ Pan-STARRS galaxies. The analysis shows a statistically
significant asymmetry between the number of SDSS galaxies with opposite spin
directions, and the magnitude and direction of the asymmetry changes with the
direction of observation and with the redshift. The redshift dependence shows
that the distribution of the spin direction of SDSS galaxies becomes more
asymmetric as the redshift gets higher. Fitting the distribution of the galaxy
spin directions to a quadrupole alignment provides fitness with statistical
significance >5$sigma$, which grows to >8$sigma$ when just galaxies with
z>0.15 are used. Similar analysis with Pan-STARRS galaxies provides dipole and
quadrupole alignments nearly identical to the analysis of SDSS galaxies,
showing that the source of the asymmetry is not necessarily a certain unknown
flaw in a specific telescope system. While these observations are clearly
provocative, there is no known error that could exhibit itself in such form.
The data analysis process is fully automatic, and uses deterministic and
symmetric algorithms with defined rules. It does not involve either manual
analysis that can lead to human perceptual bias, or machine learning that can
capture human biases or other subtle differences that are difficult to identify
due to the complex nature of machine learning processes. Also, an error in the
galaxy annotation process is expected to show consistent bias in all parts of
the sky, rather than change with the direction of observation to form a clear
and definable pattern.
The distribution of spin directions of $sim6.4cdot10^4$ SDSS spiral
galaxies with spectra was examined, and compared to the distribution of
$sim3.3cdot10^4$ Pan-STARRS galaxies. The analysis shows a statistically
significant asymmetry between the number of SDSS galaxies with opposite spin
directions, and the magnitude and direction of the asymmetry changes with the
direction of observation and with the redshift. The redshift dependence shows
that the distribution of the spin direction of SDSS galaxies becomes more
asymmetric as the redshift gets higher. Fitting the distribution of the galaxy
spin directions to a quadrupole alignment provides fitness with statistical
significance >5$sigma$, which grows to >8$sigma$ when just galaxies with
z>0.15 are used. Similar analysis with Pan-STARRS galaxies provides dipole and
quadrupole alignments nearly identical to the analysis of SDSS galaxies,
showing that the source of the asymmetry is not necessarily a certain unknown
flaw in a specific telescope system. While these observations are clearly
provocative, there is no known error that could exhibit itself in such form.
The data analysis process is fully automatic, and uses deterministic and
symmetric algorithms with defined rules. It does not involve either manual
analysis that can lead to human perceptual bias, or machine learning that can
capture human biases or other subtle differences that are difficult to identify
due to the complex nature of machine learning processes. Also, an error in the
galaxy annotation process is expected to show consistent bias in all parts of
the sky, rather than change with the direction of observation to form a clear
and definable pattern.
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