Between two galaxies a cosmic battle in medieval style

Captured images of a battle between two large galaxies colliding with each other, bumping into each other like two medieval knights engaged in a joust , at a speed of 500 kilometers per second . The images are due to the Very Large Telescope of the European Southern Observatory, combined with data from the Alma radio telescope, also of the ESO. The dynamics, described in the journal Nature and the comparison with medieval jousts is by the same authors of the research, led by Pasquier Noterdaeme, of the Institute of Astrophysics of Paris of the Franco-Chilean Laboratory of Astronomy in Chile.

The two galaxies, more than 11 billion light years apart, are gripped by their gravitational pull in a sort of dance that has already made them cross paths several times in the past and has now brought them on a collision course again. They had been observed in the past, but only now, thanks to the combination of the two very powerful observatories, has it been possible to recognize that they are in fact two very distinct structures and to understand their dynamics .

According to the study, one of the two galaxies has a special weapon: a quasar with which it is piercing its opponent. It is a very powerful nucleus that emits intense radiation powered by a supermassive black hole and that at each passage destroys the clouds of gas that make up the heart of the other galaxy . "Here we see for the first time the effect of the radiation of a quasar directly on the internal structure of the gas in an otherwise normal galaxy," noted another author of the study, Sergei Balashev of the Ioffe Institute in St. Petersburg, Russia. The battle will end only in millions of years and in the end, the researchers say, will lead to the formation of a single large galaxy at the center of which will be one or more massive black holes .