This picture, taken by Hubble’s Advanced Camera for Surveys, shows NGC 4696, a strange hook-shaped elliptical galaxy. It is the largest galaxy in the Centaurus Cluster. Full story
Credit: ESA/Hubble and NASA
A striking new image from the Hubble Space Telescope has revealed a strange hook-shaped galaxy tucked amid a field of stars.
The galaxy, dubbed NGC 4696 is an outlier among others of its type, called elliptical galaxies. These are usually roundish, uniform-looking balls of light that lack the distinctive arms and colors of spiral galaxies. [View the new Hubble photo.]
Most likely formed by collisions between spiral galaxies, elliptical galaxies experience a brief burst of star formation triggered as the interstellar dust and gas within them crash into each other. This process quickly leaves the young elliptical galaxies exhausted, without gas supplies to form new stars from. Eventually, the galaxies gradually grow older and fainter.
But NGC 4696 isn't just a ball of light; rather, it has a mottled thread of dust that curves through it, creating the hook shape.
This thread is a huge dust lane, around 30,000 light-years across, that sweeps across the face of the galaxy. Viewed at certain wavelengths, strange thin filaments of ionized hydrogen are visible within the galaxy. In this picture, these structures are visible as a subtle marbling effect across the galaxy?s bright center.
And the galaxy's surface appearance doesn't even reveal some of its most dramatic aspects. At the heart of NGC 4696, a supermassive black hole is thought to be blowing out jets of matter at nearly the speed of light. When viewed in X-ray wavelengths, such as those visible from NASA?s Chandra X-ray Observatory, huge voids within the galaxy become visible, telltale signs of these jets' enormous power.
The new photo of NGC 4696 was created from images taken using Hubble's Advanced Camera for Surveys. A 5,440-second exposure through a blue filter was combined with a 2,320-second exposure through a near-infrared filter to create the picture.
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