Liquid-Droplet as a model for the rotation curve problem

Darabi, F.

doi:10.2478/s11534-014-0487-2

Cited by 5 publications

(5 citation statements)

References 24 publications

(40 reference statements)

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“…Studies with smaller datasets of galaxies showed nonrandom spin directions of galaxies in filaments of the cosmic web [48,95,96]. Other studies showed alignment in the spin directions even when the galaxies are too far from each other to interact gravitationally [49,50], unless assuming modified Newtonian dynamics (MOND) gravity models that explain longer gravitational span [97][98][99]. It should be mentioned that the physics of galaxy rotation is still not fully understood, and it is still not clear why and how galaxies spin.…”

Section: Discussionmentioning

confidence: 99%

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

Shamir

2022

Advances in Astronomy

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The ability to collect unprecedented amounts of astronomical data has enabled the nomical data has enabled the stu scientific questions that were impractical to study in the pre-information era. This study uses large datasets collected by four different robotic telescopes to profile the large-scale distribution of the spin directions of spiral galaxies. These datasets cover the Northern and Southern hemispheres, in addition to data acquired from space by the Hubble Space Telescope. The data were annotated automatically by a fully symmetric algorithm, as well as manually through a long labor-intensive process, leading to a dataset of nearly 10 6 galaxies. The data show possible patterns of asymmetric distribution of the spin directions, and the patterns agree between the different telescopes. The profiles also agree when using automatic or manual annotation of the galaxies, showing very similar large-scale patterns. Combining all data from all telescopes allows the most comprehensive analysis of its kind to date in terms of both the number of galaxies and the footprint size. The results show a statistically significant profile that is consistent across all telescopes. The instruments used in this study are DECam, HST, SDSS, and Pan-STARRS. The paper also discusses possible sources of bias and analyzes the design of previous work that showed different results. Further research will be required to understand and validate these preliminary observations.

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Section: Discussionmentioning

confidence: 99%

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

Shamir

2022

Advances in Astronomy

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“…Studies with smaller datasets of galaxies showed nonrandom spin directions of galaxies in filaments of the cosmic web, as described in Tempel and Libeskind, 2013;Tempel et al, 2014;Dubois et al, 2014;Kraljic et al, 2021) and others. Other studies showed alignment in the spin directions even when the galaxies are too far from each other to interact gravitationally (Lee et al, 2019a,b), unless assuming modified Newtonian dynamics (MOND) gravity models that explain longer gravitational span (Sanders, 2003;Darabi, 2014;Amendola et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

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

Shamir

2022

Preprint

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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.

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“…Studies with smaller datasets of galaxies showed non-random spin directions of galaxies in filaments of the cosmic web Tempel and Libeskind, 2013;Kraljic et al, 2021). Other studies showed alignment in the spin directions even when the galaxies are too far from each other to interact gravitationally (Lee et al, 2019a,b), unless assuming modified Newtonian dynamics (MOND) gravity models that explain longer gravitational span (Sanders, 2003;Darabi, 2014;Amendola et al, 2020). It should be mentioned that the physics of galaxy rotation is still not fully understood, and it is still not clear why and how galaxies spin.…”

Section: Discussionmentioning

confidence: 99%

Analysis of $\sim10^6$ spiral galaxies from four telescopes shows large-scale patterns of asymmetry in galaxy spin directions

Shamir

2022

Preprint

View full text Add to dashboard Cite

The ability to collect unprecedented amounts of astronomical data has enabled the studying scientific questions that were impractical to study in the preinformation era. This study uses large datasets collected by four different robotic telescopes to profile the large-scale distribution of the spin directions of spiral galaxies. These datasets cover the Northern and Southern hemispheres, in addition to data acquired from space by the Hubble Space Telescope. The data were annotated automatically by a fully symmetric algorithm, as well as manually through a long labor-intensive process, leading to a dataset of nearly 10 6 galaxies. The data shows possible patterns of asymmetric distribution of the spin directions, and the patterns agree between the different telescopes. The profiles also agree when using automatic or manual annotation of the galaxies, showing very similar large-scale patterns. Combining all data from all telescopes allows the most comprehensive analysis of its kind to date in terms of both the number of galaxies and the footprint size. The results show a statistically significant profile that is consistent across all telescopes. The instruments used in this study are DECam, HST, SDSS, and Pan-STARRS. The paper also discusses possible sources of bias, and analyzes the design of previous work that showed different results. Further research will be required to understand and validate these preliminary observations.

show abstract

Liquid-Droplet as a model for the rotation curve problem

Cited by 5 publications

References 24 publications

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

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

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

Analysis of $\sim10^6$ spiral galaxies from four telescopes shows large-scale patterns of asymmetry in galaxy spin directions

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