Oworking on the riddle of are looking containing dark matter, but which are likely too weak to have escaped previous detection. The predicts the existence of a large number of these dwarfs around large galaxies like the .
It is possible to hunt these dwarf galaxies, and more generallyclose to our galaxy using like those on the network very large matrix in New Mexico (USA). Technically speaking, it is about studying radiation of of for example through the famous . Several promising gas clouds that could be associated with faint dwarf galaxies were discovered by the group of led by Elizabeth Adams of the Dutch Institute of Radio Astronomy.
These gas clouds were thought to be associated with the Milky Way and most of them probably are. But when teams — with researchers like David Sand, an associate professor of astronomy at UArizona, or Michael Jones, a postdoctoral researcher atArizona Steward Observatory and lead author of an article on these clouds and deposited in free access at— wanted to search associated with them and dwarf galaxies, they had surprises.
Thus, an unprecedented association of young blue stars forming a group calledand observed with Hubble was really in of the Virgin. Located at an estimated distance of between 48 to 72 million was discovered by the famous French astronomer (1730-1817) known for creating the famous catalog of deep sky objects named after him.
Two hypotheses for the origin of the mysterious “blue bubbles”
Other observations made with Hubble and the instruments ofof Eso in Chile revealed the existence of ” similar plants with never-before-seen features. Thus, most stars in each system are very blue and very young, rich in heavy elements that astrophysicists call which are, in fact, simply different nuclei from those of the I’ and yours all bathed in clouds that contain very little atomic hydrogen forming at the very end of dwarf galaxy-sized structures.
the article aboutreports five blue “bubbles” that are distant from the Milky Way and distant galaxies in the cluster of with which they are potentially associated, at a distance of up to 300,000 light-years.
The presence almost exclusively of blue stars, therefore young, withoutWhere actually detectable, indicates that star formation is recent. However, the presence of many metals indicates that the gas from which these stars were formed must have been in a large, ancient galaxy that had time to chemically evolve with several generations of stars performing. stellar and ending their lives in , thus ejecting the products of this nucleosynthesis into the galaxies. We must therefore see, as in the Milky Way, and yellow in abundance.
To resolve this paradox, two theories can be invoked, all involvinggas ejected from a large galaxy. The first takes the effect of exerted by one large galaxy on another, forces that would therefore have stripped the gas. The other theory involves a galaxy rapidly colliding with a mass of hot plasma in the galaxy cluster. It can be shown that the shock produces a capable of quickly ripping a mass of gas from the galaxy. We are talking about an effect called dynamic pressure stripping ( in English).
The researchers lean more towards the second hypothesis because, in order to obtain bubbles despite everything being very isolated from the surrounding galaxies, they must move quickly, which is not compatible with the tidal mechanism hypothesis.