The tell-tale signs of a galactic merger

The tell-tale signs of a galactic merger
NGC 7714 is a spiral galaxy 100 million light-years from Earth -- a relatively close neighbour in cosmic terms.The galaxy has witnessed some violent and dramatic events in its recent past. Tell-tale signs of this brutality can be seen in NGC 7714's strangely shaped arms, and in the smoky golden haze that stretches out from the galactic center -- caused by an ongoing merger with its smaller galactic companion NGC 7715, which is off the top of the frame of this image. Credit: ESA, NASAAcknowledgement: A. Gal-Yam (Weizmann Institute of Science)

The NASA/ESA Hubble Space Telescope has captured this striking view of spiral galaxy NGC 7714. This galaxy has drifted too close to another nearby galaxy and the dramatic interaction has twisted its spiral arms out of shape, dragged streams of material out into space, and triggered bright bursts of star formation.

NGC 7714 is a at 100 million light-years from Earth—a relatively close neighbour in cosmic terms.

The galaxy has witnessed some violent and dramatic events in its recent past. Tell-tale signs of this brutality can be seen in NGC 7714's strangely shaped arms, and in the smoky golden haze that stretches out from the galactic centre.

So what caused this disfigurement? The culprit is a smaller companion named NGC 7715, which lies just out of the frame of this image—but is visible in the wider-field DSS image. The two galaxies [1] drifted too close together between 100 and 200 million years ago, and began to drag at and disrupt one another's structure and shape.

As a result, a ring and two long tails of stars have emerged from NGC 7714, creating a bridge between the two galaxies. This bridge acts as a pipeline, funnelling material from NGC 7715 towards its larger companion and feeding bursts of . Most of the star-forming activity is concentrated at the bright , although the whole galaxy is sparking .

Astronomers characterise NGC 7714 as a typical Wolf-Rayet starburst galaxy. This is due to the stars within it; a large number of the new stars are of the Wolf-Rayet type extremely hot and bright stars that begin their lives with dozens of times the mass of the Sun, but lose most of it very quickly via powerful winds.

The tell-tale signs of a galactic merger
NGC 7714 is a spiral galaxy 100 million light-years from Earth — a relatively close neighbour in cosmic terms. The galaxy has witnessed some violent and dramatic events in its recent past. Tell-tale signs of this brutality can be seen in NGC 7714's strangely shaped arms, and in the smoky golden haze that stretches out from the galactic centre — caused by an ongoing merger with its smaller galactic companion NGC 7715, which is off the top of the frame of this image. Credit: ESA, NASA

This Hubble image is a composite of data capturing a broad range of wavelengths, revealing the correlation of the gas clouds and stars in the galaxy. This new picture not only reveals the intricate structure of NGC 7714, but also shows many other objects that are much further away. These background galaxies resemble faint smudges of light, some of them with spiral forms.


Explore further

Image: A Hubble sweep of the dust filaments of NGC 4217

More information: [1] The interacting pair formed by NGC 7714 and NGC 7715 is named Arp 284.
Citation: The tell-tale signs of a galactic merger (2015, January 29) retrieved 23 September 2019 from https://phys.org/news/2015-01-tell-tale-galactic-merger.html
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Jan 29, 2015
Couldn't you even get the image right? Another piss-poor job, children.

Jan 29, 2015
Once you review the latest research in plasma physics then galaxy formations and behavior can most accurately be predicted. The actions of a plasma in space mirror that of galaxies......wonder what that means for gravity and dark matter/energy??????

Jan 30, 2015
Hey! The top photo in the article is ESO's VLT CG4 image.

Please fix it!

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