Thu. Jan 20th, 2022


An image of a super-scattered galaxy studied by a team.

An image of the Ultra-DIffuse galaxy with hydrogen gas highlighted in green.
Pictures: Xavier Roman and Pavel Mansera Pina

Dark matter is invisible Something That cosmic duct gloms together like tape. But a team of researchers says they have found a distant galaxy that is completely free of dark matter, a search that could shake the idea of ​​both dark matter and galaxy formation.

Although we cannot observe Dark Matter directly (physicists believe that it creates About 27% Of the universe) We see Its effect When we look at the gravitational universe we see that all the galaxies seem to existExtra “ MassThey act as if they contain much more substance than we can actually detect ৷. In recent cases, though, A A team of astronomers tried to observe the effect of dark matter on gas rolling in distant dwarf galaxies, but they found that only normal matter could explain gas. The movement had no place for dark matter, as far as they could tell. T.His team has done research Accepted for publication In the monthly notification of the Royal Astronomical Society.

Filippo Fraternalli, an astrophysicist at the University of Groningen in the Netherlands and co-author of the research paper, told Gizmodo in an email that the galaxies the team studied could be put together. Only by this Except for its visible mass যা which sounds perfectly reasonable Dark matter is believed to be one All major components The galaxy. “The main problem is that In our galaxy formation scene, galaxies cannot form without dark matter, And moreover, dwarf galaxies should have a lot of it, “Fratarnali said.” So there’s something we don’t understand. “

The galaxy is named AGC 114905 and is about 250 million light-years from Earth. It is ultra-diffuse, which means its subject matter is spread over a huge amount of space; AGC 114905 is the size of the Milky Way But there are about 1,000 They are many times less. The research team used a very large array telescope from the National Radio Astronomy Observatory to observe the rotation of the gas in the galaxy within 40 hours, extending from July to October 2020.

A galaxy cluster.

The findings are similar to that on NGC1052-DF2, a different dwarf galaxy seemingly to lack dark matter that was  Narrated In 2018. Very fast, a Debate The demand erupted; Some astronomers thought that the galaxy was evidence of a new kind of galactic growth, while others thought that it was being misinterpreted. And that team needs more information. WowThere is no dark matter in the galaxy, it is a fairly surprising claim.

Recently, A team double-checked the measurements on NGC1052-DF2, which confirmed what the original team found about the distance to the galaxy and, thus, its dark matter content. Nicholas Martin, an astronomer at the Max Planck Institute for Astronomy, Told Gizmodo at the time The galaxy that “could have an unexpected structure and evolution” and “the good thing is that upcoming telescopes and surveys will make it easier to understand both NGC1052-DF2 and make meaningful limitations on how strange it is.” Which part of the population is currently not easily explained by galaxy formation models? Now, wWith the discovery of AGC 114905, there is further evidence that there is actually a population galaxy that only Cannot be explained by current model.

The team recently observed that the Dark Matter of AGC 114905 in and around Dark Matter Hello. The Galaxy 6 must be made of (if not completely) dark matter to match their collected data. One explanation for the absence was that the galaxy was snatched from its dark matter by nearby large galaxies except We are thereNo such thing again The galaxy around it.

“Theory predicts that AGC 114905 must contain dark matter, but our observations say it is not,” said Pavel Mansera Pina, an astronomer at the University of Groningen in the Netherlands and lead author of the paper, at a Royal Astronomical Society. Press release. “Actually, the difference between theory and observation is only getting bigger.”

Another theory was that the angle at which the team observed the galaxy made it difficult to see the dark object, but co-author Tom Osterluu, an astrophysicist at the Netherlands Institute for Radio Astronomy, stated in the same publication that the actual angle would be beautiful. Extreme compared to team estimates.

Currently, The team is investigating a second ultra-diffuse galaxy to see if it also lacks the dark matter section. If it does, it will affect the analysis of the first galaxy group. Observation now Running, And Fraternal said the team expects similar data. The more we learn about it, the more mysterious the dark matter becomes.

More: What is Dark Matter and why has no one found it yet?



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