Galaxies without dark matter are reported


byBryan Goff

Engaged in the formation of galaxies, which is also heavily involved in the movement of celestial bodiesDark matter(Dark Matter) "is not found in galaxies. A physicist discusses what "galaxy without dark matter" has meaning.

Hubble finds first galaxy in the local Universe without dark matter | ESA / Hubble
http://www.spacetelescope.org/news/heic1806/

Astrophysicists Claim They Found a 'Galaxy Without Dark Matter'
https://www.livescience.com/62151-galaxy-dark-matter-physics.html

Astronomers Boggle at Distant Galaxy Devoid of Dark Matter - Scientific American
https://www.scientificamerican.com/article/astronomers-boggle-at-distant-galaxy-devoid-of-dark-matter/

When observing the galaxy where many stars rotate, it is seen that the celestial body rotates at a speed that is significantly different from the rotation speed obtained from the law of gravity and motion. In order to explain the phenomenon that "the mass of a celestial body seems to be bigger than the actual observable," scientists have hypothesized that there is a dark matter having only mass energy without emitting light, Modify the law ofModified Newtonian mechanics(MOND) was used.

However, in a new paper, the existence of "galaxies that do not have dark matter and show movement according to physical laws" was reported.

The Hubble Space Telescope, the Gemini Observatory, and the W · M · Keck Observatory for a long time observed the galaxies called "NGC 1052-DF 2" located about 65 million light-years from the earth in the direction of the Cetacean, It is understood that it is moving according to the law of physics without requiring correction by dark matter ".

byIan Rinefort

About this paper When Live Science asked for opinions from several physicists, many said that they "commented that the paper made the existence of dark matter more plausible".

Kathryn Zurek of Lawrence Berkeley National Laboratory who is not participating in the study said that this discovery is one of the most important words to cover MOND, in response to Live Science's interview. "Dark matter in the galaxy Absence, dark matter isBaryonIt is demonstrating that it acts as a separate substance. " This means that if there is no dark matter in the universe and the MOND explains the mass problem, NGC 1052 - DF 2 should also have mass problems like elsewhere, so it is inverse It means that the existence of MOND is denied.

Mr. Zurek believes that the results of this research have made the existence of dark matter more convincing, while "galaxies without dark matter" deepen the mystery in other directions.

As of 2018, it shows how dark matter was produced in the simulation of space formation starting from the big bang. The dark matter attracts the gas drifting in space by the gravity, the gathering gathers balls, it shines, the shape of the planet and the galaxy, because the gravitational force of ordinary matter visible can not form the galaxy alone The main hypothesis is that it became. Regarding this simulation, Dan Bauer, a physicist at the Fermi National Accelerator Institute and not participating in this study, said, "If there are galaxies that do not contain dark matter, we will know how the galaxy" You must ask the question "Is it?" Mr. Bauer concludes that although the existence of NGC 1052 - DF 2 does not shake the basic principles of dark matter theory, it is "amazing and has the power to let astrophysicists develop new models of galaxy formation" I said.

Meanwhile, Stacy McGaugh, who is an astrophysicist at Case Western Reserve University and not engaged in writing thesis, is negative to the idea that this paper denies MOND and supports the existence of dark matter. "From my experience, what does not make sense in MOND does not usually make sense in dark matter as well," McGaugh said, and this discovery strengthens either theory It shows a view that it will be a challenge for both, not for both. There is also another way to form galaxies, such as "collision between galaxies".

byRodion Kutsaev

Furthermore, McGaugh points out that the conclusion of this paper is dependent on a small number of data. Researchers have figured out the rotational speed of NGC 1052 - DF 2 from ten substances in the galaxy, but according to McGaugh, 10 are insufficient to correctly measure the speed of the galaxy. "By obtaining more data, it becomes clear whether 10 data were enough or 10 were insufficient. The problem of how much data you trust is very difficult "McGaugh said. In addition, McGaugh also shows the possibility that the movement of NGC 1052 - DF 2 is influenced by neighboring galaxies, but in any case, further data is required.

in Science, Posted by logq_fa