Thatworking on the riddle of Searching for containing dark matter but which are probably very weak to have escaped previous detection. that predicts the existence of a large number of these dwarfs around large galaxies such as .
It is possible to hunt these dwarf galaxies, and more generallyclose to our Galaxy using like those of the network of Very large array in New Mexico (USA). Technically, it is a matter of studying the radiation of of e.g via The known . Thus, several promising gas clouds that could be associated with faint dwarf galaxies have been discovered by the group of led by Elizabeth Adams of the Dutch Institute of Radio Astronomy.
These gas clouds were thought to be connected to the Milky Way, and most of them probably are. But when teams – with scientists like David Sand, associate professor of astronomy at UArizona, or Michael Jones, postdoc researcher atUArizona Steward Observatory and lead author of an article on these clouds and deposited in free access onwanted to look for 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 actually by chance in of the Virgin. Located at an estimated distance of 48 to 72 million it was discovered by the famous French astronomer (1730-1817) known for having created the famous catalog of deep sky objects bearing his name.
Two hypotheses for the origin of the mysterious “blue blobs”
Other observations made with Hubble and the instruments fromof Eso in Chile has revealed the existence of ” similar drawings 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 in reality are simply other nuclei than those of I’ and their all bathed in clouds containing very little atomic hydrogen that form well at the end of the structures the size of a dwarf galaxy.
The article regardingreports five blue “blobs” distant from the Milky Way and distant galaxies in the cluster of which they are potentially associated with, from a distance of up to 300,000 light-years.
The presence almost exclusively of blue stars, therefore young, with noWhere really detectable, indicates that star formation is new. However, the presence of many metals indicates that the gas from which these stars were formed must have been in a large and ancient galaxy, which had time to evolve chemically with several generations of stars performing stars and end their lives in , thus expelling the products of this nucleosynthesis in the galaxies. We should therefore see, as in the Milky Way, and yellow in abundance.
To solve this paradox, two theories can be invoked that all involvegas expelled from a large galaxy. The first assumes the effect of exerted by a large galaxy on another, forces which would therefore have torn gas off. The second theory involves a galaxy rapidly colliding with a mass of hot plasma in the galaxy cluster. It can be shown that the shock produces one able to quickly tear a lot of gas from the galaxy. We are then talking about an effect called stripping by dynamic pressure ( English).
The scientists lean more towards the second hypothesis because in order to obtain blobs, after all, which is very isolated from the surrounding galaxies, they have to move fast, which is not compatible with the hypothesis of the mechanism of tidal forces.