By Mark Prigg
It may look like a peaceful, tranquil place, but in fact the spiral galaxy below, known as 'The River' has been the scene of two two violent supernovae in the last 30 years, scientists said today.
Called NGC 1187, the new images released today show the galaxy, which lies
about 60 million light-years from Earth and was discovered by English
astronomer William Herschel in 1784, in unprecedented detail.
The spiral galaxy lies about 60 million light-years away in the constellation of Eridanus (known as The River). NGC 1187 has hosted two supernova explosions during the last thirty years, the latest one in 2007.
The apparently peaceful spiral galaxy pictured above in the constellation Eridanus -- the River -- has hosted two violent supernovae in the last 30 years, belying its tranquillity, astronomers said.
The location of NGC 1187 in the constellation of Eridanus (The River). This galaxy appears as a faint smudge through medium-sized amateur telescopes under good conditions.
Supernovae can occur at the end of a
massive star's lifetime when its nuclear fuel is exhausted and gravity
causes it to collapse on itself, producing a violent explosion that
outshines a galaxy.
Alternatively, they can also occur in a binary star
system when a carbon-oxygen white dwarf pulls so much matter from a
higher-mass companion star that the larger star collapses on itself.
Remnants of the 2007 supernova are still visible as a small red dot at
the bottom center of the image above.
Many distant, fainter galaxies can be seen around NGC 1187, and even through it.
They are mostly red, compared to the yellow and blue of the spiral galaxy.
The galaxy is seen almost face-on, which the European Southern Observatory says gives us a unique view of its spiral structure.
'About half a dozen prominent spiral arms can be seen, each containing large amounts of gas and dust,' it explained.
'The bluish features in the spiral arms indicate the presence of young stars born out of clouds of interstellar gas.
'Looking towards the central regions, we see the bulge of the galaxy glowing yellow.
'This part of the galaxy is mostly made up of old stars, gas and dust.'
In the case of NGC 1187, rather than a round bulge, there is a subtle central bar structure.
Such bar features are thought to act as mechanisms that channel gas from the spiral arms to the centre, enhancing star formation there.
Around the outside of the galaxy many much fainter and more distant galaxies can also be seen.
Some even shine right through the disc of NGC 1187 itself. Their mostly reddish hues contrast with the pale blue star clusters of the much closer objec, the ESO says.
In October 1982, astronomers at the
European Southern Observatory's La Silla Observatory in Paranal, Chile,
observed a supernova in the galaxy.
In 2007, amateur astronomer Berto
Monard of South Africa observed a second one, which was observed with
multiple telescopes for more than a year.
The bluish features of the arms indicate the presence of young stars born out of interstellar gas, while the yellow bulge at the center is mostly made up of old stars, gas and dust.
The image was obtained using ESO's Very Large Telescope at Paranal.
This wide-field view is centred on the spiral galaxy NGC 1187 in the constellation of Eridanus (The River).