Credit: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt
Acknowledgement: Judy Schmidt
This NASA/ESA Hubble Space Telescope image shows an elliptical galaxy
called NGC 2865. It lies just over 100 million light-years away from us
in the constellation of Hydra — The Sea Serpent — and was discovered in
1835 by astronomer John Herschel.
Elliptical galaxies are usually
filled with old, dying stars. NGC 2865, however, is relatively youthful
and dynamic, with a rapidly rotating disc full of young stars and
metal-rich gas. For an elliptical galaxy it contains an unusually high
number of young stars — suggesting that a galaxy-wide starburst took
place about one billion years ago.
The starburst itself was
induced by a merger between a spiral galaxy, similar to our galaxy, the
Milky Way, and an elliptical galaxy some three times more massive — the
progenitor galaxy of NGC 2865. The new gas from the spiral galaxy
revitalised the dying population of old stars in the elliptical galaxy,
and several new generations of stars were born.
The faint halo
surrounding the galaxy, visible in this image, is also a result of this
merger. It consists of cold gas that was ripped away from the spiral
galaxy during the merging process. The gas now forms an almost closed
shell around its host galaxy.
A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Judy Schmidt.
Link:
Source: ESA/Hubble- Space Telescope
