A Dying Galaxy

[Starlyte]

A new image shows evidence for a galaxy being stripped bare of its star-forming material by its violent ongoing encounter with the hot gas in the center of a galaxy cluster, astronomers announced last week.

The picture, from the WIYN 3.5-meter telescope on Kitt Peak, was presented last week at a meeting of the American Astronomical Society.

The disruptive process is believed to influence the evolution of galaxies and their star-forming ability over time, but direct observational evidence has been somewhat scant.

The galaxy, NGC 4402, is more than 50 million light-years from Earth. It is in the midst of the relatively nearby Virgo cluster of galaxies. As the NGC 4402 moves toward the center of the cluster (located out of the image toward the bottom left), it experiences a "wind" from hot gas that permeates the cluster and which reaches temperatures of millions of degrees.

"This hot wind strips out the much cooler gas and dust in the galaxy," Hugh Crowl of Yale University. "This is important because the gas is raw material for new stars, and once this gas is stripped, the galaxy can no longer form new stars and becomes ‘dead’ in a sense."

Crowl said there are four lines of evidence:

The dust disk appears to be truncated, meaning that the light from stars extends out well beyond where gas and dust is observed. "Since we believe that stars are born in clouds of gas and dust, this suggests that some of the material must have been stripped from the galaxy after the stars were born," Crowl explains.

The dusty disk appears to be bowed upward; it has been bent by the wind blowing from the southeast (from the lower left of the image).

It appears that light emitted by the north side of the stellar disk has been reddened and dimmed by dust that has been pushed up in front of it by the pressure of the cluster gas. Simultaneously, the dust to the south of the disk has been removed, revealing young blue stars glowing behind it.

Finally, some of the most unusual features of NGC 4402 are the linear filaments of dust to the south of its main disk. "These remarkable filaments originate in clumps that appear to be the densest remnants of the now displaced disk of the galaxy," Crowl said.

-- SPACE.com Staff

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[Universal Absurdity]

Very interesting article starlyte

too bad for the galaxy, it is a pretty pic tho

[The Gryphon]

Ditto, very interesting. good photo from a terrestial telescope though!

[moe eubleck]

very good article starlyte. Its nice too see that after all this time. someone like you who................WAIT!!!

*looks out window*

They are coming!! *dramatic gasp* Grab your children! RUN! THEY ARE COMING FOR US ALL!!

[jonfr]

One galaxy death means an live for an other galaxy.

[BurnSide]

that's quite amazing and very interesting, thanks for the article!