Astronomers have discovered in the catalogue of observations of large ring-shaped galaxy with a redshift of z = 2,19 (which corresponds to the age of the Universe about 3 billion years), and it is significantly larger than typical galaxies in this region. The opening allows you to explore the processes of galactic evolution, and to further study the mechanisms of formation of such structures. The text of the paper published in the journal Nature.
To include a ring-shaped galaxy with a bright ring of stars at some distance from their Central region. The formation of objects of this type are not fully understood — there are a number of hypotheses of their origin, many of which are not mutually exclusive. One of the most probable mechanisms of formation of the stellar ring is a collision of disk galaxies with compact satellite. Such an event gives rise to a wave seal in clouds of gas, which in turn leads to the collapse of these clouds and the formation of a belt of young stars.
In the immediate vicinity of the milky Way (z < 0,1) the share of collisional ring galaxies (which have collision scenario has serious confirmation) is on the order of 0.01% to an average of ten thousand objects, only a few belong to this type. However, observations of such systems give astrophysicists the ability to more accurately simulate the processes of collision and to obtain information about the internal structure of the interacting galaxies. In some studies (1, 2) on the basis of observational sampling and theoretical considerations, examines the incidence of collisional ring galaxies, depending on the space age — it is important to determine the best region of the search objects, and to describe the process of evolution of the Universe as a whole. Consensus from the authors of such works also for a clear confirmation of the results of the necessary astronomical observations.
Scientific group under the leadership of yuan, day by day hotel (Tiantian Yuan) from Swinburne University of Technology in Melbourne began searching for galaxies with ring-shaped structures. To do this, the scientists treated the directory images the Magellan telescope in the Chilean Observatory of Las Campanas, which he made during a programme to study galaxies at far distances (z > 1) from the Ground. Among the four thousand found objects one of the most important was the galaxy R5519, which, together with that possessed a pronounced annular structure.
To clarify the position of the galaxy, astronomers measured its spectrum in the near infrared range on the basis of the Keck Observatory in Hawaii. Around the object, the authors found a small group of galaxies to estimate the distances between them, scientists have used the data of one of the missions the Hubble space telescope (Hubble Space Telescope), which lasted for 18 and 19 cycles of operation of the apparatus. One of the neighbors R5519, researchers estimate, could run into her a few dozen million years ago and caused the formation of this ring.