Theworking on the riddle of they are looking for containing dark matter but which are likely very faint from having escaped a previous detection. the predicts the existence of a large number of these dwarfs around large galaxies such as the .
It is possible to hunt these dwarf galaxies, and more generallynear our galaxy using like those of the network of Very large matrix in New Mexico (United States). Technically it is a question of studying radiation from from For instance through the famous . Several promising gas clouds that could be associated with faint dwarf galaxies were therefore discovered by the group of led by Elizabeth Adams of the Dutch Radio Astronomy Institute.
These gas clouds were thought to be associated with the Milky Way and most of them probably are. But when teams – with researchers such as David Sand, associate professor of astronomy at Arizona, or Michael Jones, postdoctoral researcher atObservatory for Arizona Stewards and lead author of an article on these clouds and deposited in free access on– I wanted to search associated with them and the dwarf galaxies, they had surprises.
Thus, an unprecedented association of young blue stars forming a group calledand observed with Hubble was actually in the of the Virgin. Located at an estimated distance of between 48 and 72 million it was discovered by the famous French astronomer (1730-1817) known for creating the famous catalog of deep-sky objects that bears his name.
Two hypotheses for the origin of the mysterious “blue spots”
Other observations made with Hubble and the instruments of theof Eso in Chile revealed the existence of ” similar projects with features never seen before. Therefore, most of the stars in each system are very blue and very young, rich in heavy elements that astrophysicists call which are, in fact, simply nuclei different from those of L’ it’s theirs all immersed in clouds that contain very little atomic hydrogen forming well at the end of the structures the size of a dwarf galaxy.
The article onreports five blue “spots” that are distant from the Milky Way and distant galaxies in the cluster of with which they are potentially associated, from a distance of up to 300,000 light years.
The presence almost exclusively of blue stars, therefore young, with nWhere is it truly detectable, it indicates that the star formation is recent. However, the presence of many metals indicates that the gas from which these stars formed must have been in a large and ancient galaxy that has had time to chemically evolve with several generations of stars in stellar and finish their life in , thus expelling the products of this nucleosynthesis into galaxies. We should therefore see, as in the Milky Way, and yellows in abundance.
To resolve this paradox, two theories can be invoked, all involvinggas expelled from a large galaxy. The first takes on the effect of exerted by one large galaxy on another, forces that would then have ripped off gas. The other theory concerns 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 rapidly stripping a mass of gas from the galaxy. We therefore speak of an effect called dynamic pressure stripping ( in English).
The researchers are more oriented towards the second hypothesis because, in order to obtain blobs despite everything that are very isolated from the surrounding galaxies, they must move quickly, which is not compatible with the hypothesis of the mechanism with tidal forces.