No dark matter halos

No dark matter halos

The dwarf galaxy NGC1427A flies through the Fornax galaxy cluster and undergoes turbulence that would not have been possible if this galaxy were surrounded by a heavy, stretching dark matter halo, as required by standard cosmology. Credit: ESO

According to the Standard Model of cosmology, the vast majority of galaxies are surrounded by a halo of dark matter particles. This halo is invisible, but its mass exerts a strong gravitational force on neighboring galaxies. A new study by the University of Bonn (Germany) and the University of St Andrews (Scotland) challenges this view of the universe. The results indicate that dwarf galaxies in the second closest galaxy cluster to Earth – known as the Fornax Cluster – are devoid of dark matter halos. The study appeared in the journal Monthly Notices of the Royal Astronomical Society.

Dwarf galaxies are small, faint galaxies that can usually be found galaxy clusters or near larger galaxies. For this reason, they may be affected by the gravitational effects of their larger companions. We offer an innovative way to test Standard Form Based on how much dwarf galaxies are disturbed by gravity, the tides from larger nearby galaxies, said Elena Ascencio, a doctoral student at the University of Bonn and lead author of the story. Differently in different parts of another body, these are similar to Earth’s tides, which arise due to the Moon being pulled more strongly on the side of the Earth that faces the Moon.

The Fornax Cluster contains a large number of dwarf galaxies. Recent observations show that some of these dwarves look disfigured, as if they were disturbed before gathering environment. “Such disturbances in Fornax dwarfs are not expected according to the standard model,” said Pavel Krupa, a professor at the University of Bonn and Charles University in Prague. “This is because according to the standard ModelThe Dark matter halos From these dwarves you shall partly protect them from the tides raised by the mass.”

The authors analyzed the expected level of turbulence of the dwarfs, which depends on their internal characteristics and their distance from the gravitationally strong cluster center. Galaxies of large but low-mass stellar masses and galaxies close to the center of the cluster are easy to disturb or destroy. They compared the results to the level of perceived turbulence evident from images taken with the European Southern Observatory’s VLT Survey Telescope.

“The comparison showed that if one wants to explain observations in the Standard Model, Fornax dwarfs must indeed be destroyed by gravity from the center of mass even when the tides they raise on a dwarf are sixty-four times weaker than the dwarf’s self-gravity,” says Elena Asencio. Not only is this counter-intuitive, she said, it also contradicts previous studies, which have found that the external force needed to perturb a dwarf galaxy is roughly the same as the dwarf’s self-gravity.

Contradiction with the Standard Model

From this, the authors conclude that, in the Standard Model, the observed morphology of Fornax dwarfs cannot be explained in a self-consistent manner. They repeated the analysis using Milgromian dynamics (MOND). Rather than assuming dark matter halos surrounding galaxies, MOND theory proposes a correction for Newtonian dynamics in which gravity experiences a boost in the low acceleration regime.

“We were not sure that the file dwarf galaxies It would be able to survive in the harsh environment of a galaxy cluster at MOND, due to the absence of protective dark matter halos in this model,” said Dr. Indranil Banik from the University of St Andrews. But our results show a remarkable agreement between MOND’s observations and predictions for the level of Fornax dwarfism.”

said Akko Venhola of the University of Oulu (Finland) and Stephen Miski of the European Southern Observatory, who are co-authors of the study.

This is not the first time that a study examining the effect of dark matter on the dynamics and evolution has been tested galaxies He concluded that observations are best explained when they are not surrounded by dark matter. Pavel Krupa, a member of the Interdisciplinary Research Areas Modeling and . said: issue at the University of Bonn.

Dr Hongsheng Zhao of the University of St Andrews added, “Their results have major implications for basic physics. We expect to find more perturbed dwarfs in other groups, a prediction that other teams should verify.”


A new rotation in the galaxy preserves the controversial theory of gravity


more information:
Elena Asencio et al, The distribution and formations of the dwarf Fornax Cluster galaxies indicate that they lack dark matter, Monthly Notices of the Royal Astronomical Society (2022). DOI: 10.1093/mnras/stac1765

Introduction of
Bonn University


the quote: No trace of dark matter halos (2022, August 5) Retrieved August 6, 2022 from https://phys.org/news/2022-08-dark-halos.html

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