2021-01-13

For the first time: astronomers witness the death of galaxies

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UK Scientists from the University of Durham and the Thackeray Nuclear Research Center in France have used Chile’s Atacama Large Millimeter Wave Telescope Array (ALMA) to observe this rare phenomenon, and even see that the cold gas used to form stars is growing in large quantities. Drain.

For the first time: astronomers witness the death of galaxies

This galaxy is codenamed ID2299, approximately 9 billion light years. The ID2299 galaxy now loses the equivalent of 10,000 solar masses of gas each year, which has led to a significant reduction in the materials needed to form stars. So far, the galaxy has lost 46% of its total cold gas.

Meanwhile, ID2299 is still rapidly forming new stars hundreds of times faster than our Milky Way galaxy, which will further accelerate the depletion of the remaining gas in the galaxy. This will actually cause ID2299 to die in tens of millions of years.

Annagrazia Puglisi, principal researcher and postdoctoral assistant at the University of Durham in the United Kingdom and the Thackeray Nuclear Research Center in France, said: “This is the first time we have observed A scene where a huge galaxy is about to die because its cold gas is being ejected and lost on a large scale.”

The demise of this galaxy may be due to collisions with other galaxies. Strong evidence that a collision may cause gas loss is the formation of a “tidal tail,” which is a long stream of gas and stars that extends into space after two galaxies collide. Normally, these tidal tails are difficult to see from such a distant place, but astronomers can observe it when the bright tail extends into space.

If the collision causes gas loss in this galaxy, astronomers may need to reconsider theories about the process of star formation in the galaxy. Previously, scientists believed that the wind generated by star formation, combined with the active black hole in the center of giant galaxies, would eject the material needed to form stars out of space, marking the end of the star formation process.

Astronomer Emanuele Daddi, a research co-author of the French Saclay Nuclear Research Center, said: “Our research shows that collisions can produce gas eruptions, wind and tidal tails. It looks very similar. This may change our understanding of the “death” of galaxies.”

Continuous observations of ID2299 in the future may reveal more information about the gas emitted by the galaxy. Chiara Circosta, a researcher at University College London, said: “ALMA provides new clues to explain the mechanism of star formation in distant galaxies. Witnessing such a large-scale destruction event is a mystery of complex galaxy evolution. Added an important link.”