January 19, 2021

Capture for the first time the beginning of the end of a distant galaxy


Observatory in the Atacama desert, in Chile.

Observatory in the Atacama desert, in Chile.
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Astronomers in the Atacama observatory, in the north of Chile, have managed to capture for the first time andThe beginning of the end of a distant galaxy, which will allow them to rethink how galaxies stop giving life to new stars.

Scientists managed to capture the death of a distant colliding galaxy due to the expulsion of almost half of its gas, the fundamental element for the formation of stars, as revealed this Monday by the European Southern Observatory (ESO).

The image shows the expulsion of gas taking place at a “surprising” rate., equivalent to the gas that would be needed to form 10,000 suns a year and that is removing 46% of the total cold gas of the galaxy in question.

Until now, astronomers knew that galaxies begin to “die” when they stop forming stars, but never before had they clearly glimpsed the beginning of this process in a distant galaxy.

“This is the first time that we have observed a typical massive star-forming galaxy in the distant universe about to die due to a massive ejection of cold gas,” he explains. Annagrazia Puglisi, principal investigator of the new study, from Durham University (UK) and the Saclay Nuclear Research Center (CEA-Saclay, France).

Scientists have been able to use the Atacama facilities to understand what happened: this event was triggered by a collision with another galaxy with which they eventually merged to form the galaxy known as “ID2299”.

“Our study suggests that gas ejections can be caused by mergers between galaxies“says the study co-author, Emanuele Daddi, from CEA-Saclay (France), who assures that this forces us to review the understanding of how galaxies ‘die’.

The clue that led the ESO team to this scenario was the association of the expelled gas as a “tidal tail“, elongated streams of stars and gas that extend in interstellar space and that are the result of the merger of two galaxies.

Most astronomers believe that winds caused by star formation and the activity of black holes at the centers of massive galaxies are responsible for launching star-forming material into space, thus ending the ability of galaxies to create new stars.

However, this new image suggests that galactic mergers may also be responsible for expelling the fuel needed for star formation into space.

Chiara circosta, a researcher at University College London (UK), says that the study has shed “new light” on the mechanisms that can stop the formation of stars in distant galaxies.

“Witnessing such a massive disruptive event adds an important piece to the complex puzzle of the evolution of galaxies“adds Circosta.

The contribution of the Chilean observatory has been essential, but astronomers already rely on making deeper and higher resolution observations of this galaxy, to better understand the dynamics of the expelled gas.

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