Astronomers of the Netherlands, together with colleagues from other countries, found that the Galaxy AGC 114905 does not contain traces of the existence of dark matter. The observations of the galaxy were carried out within 40 hours with a number of modern telescopes. The results are accepted for publication in the journal MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. They are described in detail in preprint available in the ARXIV repository.
The Galaxy AGC 114905 is located at a distance of 250 million light years and is classified as a ultra-dipped dwarf galaxy due to low luminosity. Although it is comparable with the Milky Path, it contains a thousand times less than stars. Among scientists are dominated by the opinion that ultra-dippedic galaxies can only exist if they contain dark matter, providing sufficient mass for gravitational retention of a substance and launch of star formation processes.
researchers conducted observations of the galaxy from July to October 2020 to collect data on the speed of rotation of the gas depending on the distance to the center of AGC 114905. The results demonstrated that gas movement in the galaxy is fully explained by the influence of a conventional substance, that is, It does not have dark matter. This creates a problem for modern ideas about the evolution of ultra-dipped galaxies.
This may be a few explanations. First, dark matter could be brought by the gravitational forces of nearby massive galaxies. However, in the case of AGC 114905 there are no such galaxies nearby. Secondly, the result may affect the angle under which the astronomers carried out observations of the galaxy. The authors note that this angle in reality can strongly deviate from the meaning that they used in the calculations. However, the error associated with this still remains not enough to agree to agree on the behavior of AGC 114905 with a model of cold dark matter or a modified Newtonian mechanics.
At present, scientists conduct observations of the second ultra-dipped dwarf galaxy. If in her case, astronomers do not again find traces of dark matter, it will be convincing evidence in favor of the existence of galaxies devoid of dark matter.
The cold dark matter model explains the problem of the hidden mass in galaxies, which is that the visible substance cannot explain the high speed of rotation of stars, sufficiently removed from the kernel. According to Newtonian mechanics, this speed should be below the observed. An alternative theory, called the modified Newtonian mechanics (Mond), rejects the model of dark matter and introduces changes to Newton’s laws.