How Galactic Mergers Contribute to the Death of Galaxies [STUDY]

Scientists' observations with the Atacama Large Millimeter/submillimeter Array (ALMA) and Hubble appeared to reveal the cause of SDSS J1448+star 1010's formation halt. The unexpected results imply that both slower processes, such as galactic mergers, and faster events, can contribute to the cessation of star formation, sometimes referred to as the death of galaxies.

Formation and Death of SDSS J1448+1010

When the universe was about half its present age of 13.8 billion years old, SDSS J1448+1010 was created by the collision of two progenitor galaxies. As a result, the gravitational pull of each galaxy created a cosmic tug of war. This conflict tore the stars and gas from the resulting galaxy, leaving it with a vast flow of material emerging from it that astronomers refer to as a tidal tail.

According to Astronomy, two tidal tails-one trailing and one leading each galaxy-are frequently formed during the encounter as a result of the removal of gas and stars from the galaxies' outer regions.

Around half of the galaxy's cold star-forming gas, or 10 billion times the mass of the sun, is present in the SDSS J1448+ 1010 tail. This suggests that the merger may have stopped star formation in the galaxy's current inactive state.

Astronomers used the Hubble Space Telescope and the ALMA in Northern Chile to observe the merger, which is now almost complete.

Astronomer Justin Spilker of Texas A&M University explained that what first made this large galaxy noteworthy was that, for whatever reason, right after a surge of star-making activity approximately 70 million years ago, it suddenly stopped creating stars. Most galaxies, he claimed, continue generating stars.

How Do Galaxies Live and Die?

According to a study that was published in Arxiv in 2021, the dying galaxies simply ran out of gas, which is the fuel for star formation. Where the gas disappeared and why it isn't being replaced are still mysteries.

To try to build anything, according to co-author and associate professor of astronomy Desika Narayanan, requires a certain quantity of fuel. Stars push back against parent clouds and obliterate their homes once enough of them have formed. However, that process only uses a modest amount of gasoline. The remaining gas just disperses.

Wren Suess, a cosmologist at the University of California, Santa Cruz, and co-author of the current study published in The Astrophysical Journal Letters, said that because those extinct galaxies contain a large number of old stars, they must have generated all of those stars at some point in the past before stopping doing so. This finding demonstrates the strength of these large galaxy mergers and the extent to which they can influence a galaxy's evolution.

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Next Stage in Dead Galaxy Research

Finding out how frequently galactic tugs of war like the one that gave SDSS J1448+1010 its huge tail are and whether they are frequently associated with dormant galaxies that have halted star formation may be the next stage in this research.

That would entail identifying further instances of galaxies similar to SDSS J1448+1010 or researching galaxies similar to J1448+1010 that astronomers have already been fortunate enough to observe during a collision.

Spilker came to the conclusion that astronomers previously believed the only way to halt galaxies from creating stars was by extremely violent, quick processes, such as a number of supernovae exploding in the galaxy to blow most of the gas out of the galaxy and heat up the remaining gas. The latest findings demonstrate that star creation can be stopped without a flashy mechanism. Star formation and galaxies may come to a halt as a result of the considerably slower merging process.