Analysis of ∼106 Spiral Galaxies from Four Telescopes Shows Large-Scale Patterns of Asymmetry in Galaxy Spin Directions

Shamir, Lior

doi:10.1155/2022/8462363

Cited by 7 publications

(13 citation statements)

References 139 publications

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“…Analysis was also done by combining galaxies imaged by several sky surveys into a single analysis. Such experiment can increase the number of galaxies, but also the footprint size, and therefore can provide a more accurate location of the axis [197]. Combining the galaxies from SDSS, DESI Legacy Survey, Pan-STARRS, and HST datasets described in Section 2 led to a dataset of 958,841 galaxies [197].…”

Section: Resultsmentioning

confidence: 99%

“…Such experiment can increase the number of galaxies, but also the footprint size, and therefore can provide a more accurate location of the axis [197]. Combining the galaxies from SDSS, DESI Legacy Survey, Pan-STARRS, and HST datasets described in Section 2 led to a dataset of 958,841 galaxies [197]. Figure 8 displays the result of applying the analysis to the combined dataset.…”

Section: Resultsmentioning

confidence: 99%

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Asymmetry in Galaxy Spin Directions—Analysis of Data from DES and Comparison to Four Other Sky Surveys

Shamir

2022

Universe

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The paper shows an analysis of the large-scale distribution of galaxy spin directions of 739,286 galaxies imaged by DES. The distribution of the spin directions of the galaxies exhibits a large-scale dipole axis. Comparison of the location of the dipole axis to a similar analysis with data from SDSS, Pan-STARRS, and DESI Legacy Survey shows that all sky surveys exhibit dipole axes within 52° or less from each other, well within 1σ error, while non-random distribution is unexpected, the findings are consistent across all sky surveys, regardless of the telescope or whether the data were annotated manually or automatically. Possible errors that can lead to the observation are discussed. The paper also discusses previous studies showing opposite conclusions and analyzes the decisions that led to these results. Although the observation is provocative, and further research will be required, the existing evidence justifies considering the contention that galaxy spin directions as observed from Earth are not necessarily randomly distributed. Possible explanations can be related to mature cosmological theories, but also to the internal structure of galaxies.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Asymmetry in Galaxy Spin Directions—Analysis of Data from DES and Comparison to Four Other Sky Surveys

Shamir

2022

Universe

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“…When assigning the galaxies with random spin directions, the asymmetry disappears [159,[164][165][166]168,169,200]. For instance, Figure 7 shows the probabilities of a dipole axis in different (α, δ) combinations formed by the DES galaxies, when each galaxy is assigned a random spin direction.…”

Section: Resultsmentioning

confidence: 99%

“…Analysis was also done by combining galaxies imaged by several sky surveys into a single analysis. Such experiment can increase the number of galaxies, but also the footprint size, and therefore can provide a more accurate location of the axis [200]. Combining the galaxies from SDSS, DESI Legacy Survey, Pan-STARRS, and HST datasets described in Section 2 led to a dataset of 958,841 galaxies [200].…”

Section: Resultsmentioning

confidence: 99%

“…Such experiment can increase the number of galaxies, but also the footprint size, and therefore can provide a more accurate location of the axis [200]. Combining the galaxies from SDSS, DESI Legacy Survey, Pan-STARRS, and HST datasets described in Section 2 led to a dataset of 958,841 galaxies [200]. Figure 8 displays the result of applying the analysis to the combined dataset.…”

Section: Resultsmentioning

confidence: 99%

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Asymmetry in Galaxy Spin Directions -- Analysis of Data from DES and Comparison to Four Other Sky Surveys

Shamir¹

2022

Preprint

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The paper shows an analysis of the large-scale distribution of galaxy spin directions of 739,286 galaxies imaged by DES. The distribution of the spin directions of the galaxies exhibits a large-scale dipole axis. Comparison of the location of the dipole axis to a similar analysis with data from SDSS, Pan-STARRS, and DESI Legacy Survey shows that all sky surveys exhibit dipole axes well within 1$\sigma$ error from each other. While non-random distribution is unexpected, the findings are consistent across all sky surveys, regardless of the telescope or whether the data were annotated manually or automatically. Possible errors that can lead to the observation are discussed. The paper also discusses previous studies showing opposite conclusions, and analyzes the decisions that led to these results. Although the observation is provocative, and further research will be required, the existing evidence justifies to consider the contention that galaxy spin directions as observed from Earth are not necessarily randomly distributed. Possible explanations can be related to mature cosmological theories, but also to the internal structure of galaxies.

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Is the observable Universe consistent with the cosmological principle?

Aluri

Cea

Chingangbam

et al. 2023

Class. Quantum Grav.

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The Cosmological Principle (CP) -- the notion that the Universe is spatially isotropic and homogeneous on large scales -- underlies a century of progress in cosmology. It is conventionally formulated through the Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) cosmologies as the spacetime metric, and culminates in the successful and highly predictive $\Lambda$-Cold-Dark-Matter ($\Lambda$CDM) model. Yet, tensions have emerged within the $\Lambda$CDM model, most notably a statistically significant discrepancy in the value of the Hubble constant, $H_0$. Since the notion of cosmic expansion determined by a single parameter is intimately tied to the CP, implications of the $H_0$ tension may extend beyond $\Lambda$CDM to the CP itself. This review surveys current observational hints for deviations from the expectations of the CP, highlighting synergies and disagreements that warrant further study. Setting aside the debate about individual large structures, potential deviations from the CP include variations of cosmological parameters on the sky, discrepancies in the cosmic dipoles, and mysterious alignments in quasar polarizations and galaxy spins. While it is possible that a host of observational systematics are impacting results, it is equally plausible that precision cosmology may have outgrown the FLRW paradigm, an extremely pragmatic but non-fundamental symmetry assumption.

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Analysis of ∼106 Spiral Galaxies from Four Telescopes Shows Large-Scale Patterns of Asymmetry in Galaxy Spin Directions

Cited by 7 publications

References 139 publications

Asymmetry in Galaxy Spin Directions—Analysis of Data from DES and Comparison to Four Other Sky Surveys

Asymmetry in Galaxy Spin Directions—Analysis of Data from DES and Comparison to Four Other Sky Surveys

Asymmetry in Galaxy Spin Directions -- Analysis of Data from DES and Comparison to Four Other Sky Surveys

Is the observable Universe consistent with the cosmological principle?

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