According to Daily Mail media reports, at present, astronomers found a hidden “ghost galaxy” behind the Milky Way disk, the galaxy is called “Antila 2” (Antila 2) It is 10,000 times darker than another detected satellite galaxy in the Milky Way and is considered a dwarf galaxy.
The dark galaxies were discovered by an international research team. They obtained observations from the European Space Agency’s Gaia satellite. Gaia satellites are often used to search for ancient, metal-poor stars in dimly lit galaxies. Gabriel Torrealba, the first author of the report, said: “This is a ghost galaxy, a diffuse object like the ‘Antilla 2 galaxy’ that has never been discovered before. Thanks to the Gaia satellite.”
The researchers pointed out that the dwarf galaxies were the earliest formed celestial bodies in the early days of the universe. Despite its large size, it released much less light than expected. They used the RR Lyrae observation data to locate the hidden near the Milky Way. Celestial body. It is reported that the Tianqin RR variable star is a short-period variable star with a dimming period between 1.2-30 hours. It usually exists in some globular clusters, so it is also called “short-period variable star” or “star cluster variable star”.
Vasily Belokurov, co-author of the research report and the Institute of Astronomy at the University of Cambridge, said: “The satellite dwarf galaxies we have observed so far have the celestial RR variable star, so when we are in the galaxy We were not surprised when we observed a group of celestial RR variable stars above.”
But when we look at the universe more closely, we find some new celestial bodies, because we did not find previously identified objects when we searched for any astronomical database. After observing these stars, the team realized that they had limited time to get more data because the movement of the Earth would soon make the Antilla 2 galaxies undetectable for months. But the researchers were able to measure more than 100 red giant stars in time so they could confirm the findings. The research team pointed out that the Antilla 2 galaxies are 130,000 light-years away from the Milky Way, and its quality is much smaller than expected.
Sergey Koposov of the study, co-author and Carnegie Mellon University, said: “The simplest explanation about why the Antilla 2 galaxy is very small today is that it is being a galaxy. The tidal force of the galaxy is torn.” However, the size of the Antillian 2 galaxy has not yet been explained. Normally, when the galaxy loses mass due to the tidal force of the Milky Way, the galaxy will shrink rather than grow. It is unclear what causes the Antila 2 galaxy to be extremely large in size, but the brightness is very dark, although some people suspect that the active star has played an important role.
The study’s co-author, Jason Sanders, said: “Even if the birth of a star can reshape the dark matter distribution of the Antilla 2 galaxies, its efficiency is certainly unprecedented.”
Another research report co-author, Matthew Walker of Carnegie Mellon University, said: “The Antilla 2 galaxy is very strange compared to the other 60 satellite galaxies in the Milky Way. We Want to know if galaxies like this are just the tip of the iceberg, the Milky Way is surrounded by a large, almost invisible dwarf galaxies, like the dwarf galaxies of the Antilla 2 galaxies.”
How many years old is the oldest star in the Milky Way?
The newly discovered star is considered to be one of the oldest stars in the Milky Way. Scientists at the Institute of Astrophysics (IAC) in Spain believe that it may have formed about 300 million years after the Big Bang.
Jonay González Hernández, a researcher at the Institute of Astrophysics, said: “Theoretical predictions show that these oldest stars were formed shortly after the big bang, and the material they formed came from The earliest supernova in the universe.”
The researchers hope that the J0815+4729 star in the Bobcat constellation will help them understand the big bang more. The current big bang is a mainstream theory of the evolution of cosmic galaxies.
Rafael Rebolo, director of the Institute of Astrophysics, said: “Detecting lithium will provide us with important information related to nucleosynthesis. We are studying a high resolution, wide Spectrometers in the spectral range to measure the detailed chemical composition of a particular star, eg J0815+4729 stars.”