Tuesday , January 18 2022

Outside the Milky Way, a newly discovered massive satellite can be filled with galaxies and dark matter.


Astronomers have found that the ghostly dwarf galaxy, Antlia 2, is hidden around the Milky Way, but it is about the same size as the Large Magellanic Cloud (LMC), but its astigmatism has been avoided several times with a total luminosity of 10,000 times. Home examination. Also, although galaxies are quite large, there is little star in the galaxy, which can challenge the formation of very interesting galaxies and dark matter models for astronomers.

Members of the international team include the Astronomy Institute at Cambridge University, Imperial College of Technology in London, Gabriel Torrealba (senior author of the study) at Carnegie Mellon University and Astronomy and Astrophysics Institute at Academia Sinica.

Initially, Gabriel Torrealba decided to screen and analyze the "RR Lyrae star" from the Gaia data from the European Space Agency. This ancient metal poor star is a galaxy galaxy, a major member of the Milky Way. The lira RR type variable stars are widely distributed in galaxies, galaxies and globular clusters. Because the RR type variability luminosity is relatively high, the observations are easy to discern and can be used to study the age of globular clusters, the evolution of stars, the dynamics and evolution of the Milky Way, after determining the distance between the Milky Way globular clusters and the adjacent galaxies.

But Vasily Belokurov, an astronomer and research co-author at the University of Cambridge in the UK, said, "Because the Lyra RR type stars are very rare, "When the team saw three Lyra RR variations at 420,000 light years at a time, I was surprised that this was" overwhelming "compared to the amount of stars in the area.

The researchers began to observe the location of the star of the RR type in the sky, and were surprised to find a large number of new objects without any database in any database. The researchers measured the spectra of more than 100 giant stars and finally confirmed the ghost galaxy Antlia 2, which was around the Milky Way. Most of the stars were pulled by the gravity of the galaxy and the galaxy was turning 130,000 light years from the galaxy.

▲ Brightness comparison between Antlia 2 Galaxy, Milky Way and Large Magellanic Cloud. (Source: Chinese Academy of Sciences)

The researchers also calculated the quality of the galaxy, but in terms of size comparable to the large Magellanic Cloud (LMC), the quality is very small (100 times smaller than similar galaxies) I can not explain how big it is, but the number of stars is too small.

Previous studies have shown that many young stars are larger in magnitude because the galaxy's explosive explosion can cause gas and dust to explode in the galaxy, causing the entire galaxy to "bubble up". Nonetheless, the team think that the unbalanced size of the Antlia 2 galaxy is difficult to explain.

With this in mind, researchers need to rethink the obscure dark matter that theoretically maintains theoretically a galaxy of unequal size and mass, says Dr. Alex Geringer-Sameth of Physics at the Imperial College in Antlia, UK. 2 New basic forces can work in the galaxy, and dark matter may not be as simple as a standard cosmological model.

Dr Matthew Walker, co-author of Carnegie Mellon University, pointed out that the Antlia 2 dwarf galaxy is unique or just the tip of the iceberg. Is it possible that the galaxy will be filled with a large number of galaxies that are almost invisible?

(Source of the first picture: Academia Sinica)

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