Dying Galaxy Found Bleeding Out Into Space

This ultraviolet image of dwarf galaxy IC 3418 in the Virgo cluster shows a trail of fireballs of gas left behind it - evidence that the galaxy is dying.  Credit:NASA/JPL-Caltech/SDSS
This ultraviolet image of dwarf galaxy IC 3418 in the Virgo cluster shows a trail of fireballs of gas left behind it – evidence that a new study says points to the imminent death of this galaxy. Credit:NASA/JPL-Caltech/SDSS

 

A team of international astronomers are investigating what looks like the impending death of a dwarf galaxy 54 million light years away.

The scientists were clued in by a trail of fireballs streaming thousands of light years behind the small galaxy known as IC 3418.

The astronomers liken these bright blobs of gas, lit up by newly-formed stars, to the last drops of blood from the dying galaxy, draining out into space.

“We think we’re witnessing a critical stage in the transformation of a gas-rich dwarf irregular galaxy into a gas-poor dwarf elliptical galaxy—the depletion of its lifeblood,” said Jeffrey Kenney of Yale University, lead author of the yet-be-be published study in a press statement released this week at the 222nd meeting of the American Astronomical Society in Indianapolis.

“Until now, there has been no clear example of this transformation happening.”

The most vigorous phase of a galaxy’s life is spent as a giant star factory, pumping out generation after generation of countless of stars. But observers have found that once the inherent gas reservoir is depleted, the death process begins.

Using the WIYN 3.5-meter telescope in Arizona and the twin Keck 10-meter telescopes in Hawaii, astronomers were able to determine that IC 3418 has used up all its gas and is pretty much running on empty now.

“Stars, planets, and life can form only if a galaxy has gas to make them,” added Kenney.

What caused the traumatic wounds that led to this draining of gas?

A process called “ram pressure stripping” is the leading suspect in this cosmic crime. As gases mix between galaxies, huge pressure  builds. As a result, the gas within the galaxy is forced out and forms fireball features.

Kenny and his team now hope that by studying the death process of IC 3418  they will gain a better understanding of the full life cycle of all dwarf ellipticals—one of the universe’s most common type of galaxies. (Related: Dwarf Galaxy Found Secretly Feasting on Smaller Dwarf)

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Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.