- Galaxy NGC 4666, a starburst galaxy
- “Superwind” of gas being blow into space
- Powered by supernova explosions and hot stars
The prominent galaxy NGC 4666 in the centre of the picture is a “starburst” galaxy, about 80 million light-years from Earth, in which particularly intense star formation is taking place.
The starburst is thought to be caused by a gravitational tug-of-war between NGC 4666 and its neighbouring galaxies, including NGC 4668, visible to the lower left. These interactions often spark vigorous star-formation in the galaxies involved.
A combination of supernova explosions and strong winds blowing out from massive stars in the starburst region drives a vast flow of gas from the galaxy into intergalactic space—a so-called “superwind”. The superwind is huge in scale, coming from the bright central region of the galaxy and extending for tens of thousands of light-years.
As the superwind gas is very hot it emits radiation mostly as X-rays and in the radio part of the spectrum and cannot be seen in visible light images such as the one presented here.
The image was taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile.
See the full-size, high-resolution image here (new window).
In order to fully understand the nature of astronomical objects, researchers must study them at several wavelengths. This is because light of different wavelengths can tell us about different physical processes taking place.
This image was made as part of a follow-up to observations made with the European Space Agency’s XMM-Newton X-ray space telescope (see image at left). NGC 4666 was the target of the original XMM-Newton observations, but thanks to the telescope’s wide field-of-view many other X-ray sources were also seen in the background.
One such serendipitous detection is a faint galaxy cluster seen close to the bottom edge of the image, right of centre. This cluster is much further away from us than NGC 4666, at a distance of about three billion light-years.
Adapted from information issued by ESO / J. Dietrich / M. Ehle / ESA.
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