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About 35 million light-years from Earth,
in the constellation of Eridanus (The River), lies the spiral galaxy NGC
1637. Back in 1999 the serene appearance of this galaxy was shattered
by the appearance of a very bright supernova. Astronomers studying the
aftermath of this explosion with ESO’s Very Large Telescope at the
Paranal Observatory in Chile have provided us with a stunning view of
this relatively nearby galaxy.
Supernovae are amongst the most violent events in nature. They mark
the dazzling deaths of stars and can outshine the combined light of the
billions of stars in their host galaxies.
In 1999 the Lick Observatory in California reported the discovery of a
new supernova in the spiral galaxy NGC 1637. It was spotted using a
telescope that had been specially built to search for these rare, but
important cosmic objects .
Follow-up observations were requested so that the discovery could be
confirmed and studied further. This supernova was widely observed and
was given the name SN 1999em. After its spectacular explosion in 1999,
the supernova’s brightness has been tracked carefully by scientists,
showing its relatively gentle fading through the years.
The star that became SN 1999em was very massive — more than eight
times the mass of the Sun — before its death. At the end of its life its
core collapsed, which then created a cataclysmic explosion .
When they were making follow up observations of SN 1999em astronomers
took many pictures of this object with the VLT, which were combined to
provide us with this very clear image of its host galaxy, NGC 1637. The
spiral structure shows up in this image as a very distinct pattern of
bluish trails of young stars, glowing gas clouds and obscuring dust
Although at first glance NGC 1637 appears to be a fairly symmetrical
object it has some interesting features. It is what astronomers classify
as a lopsided spiral galaxy: the relatively loosely wound spiral arm at
the top left of the nucleus stretches around it much further than the
more compact and shorter arm at the bottom right, which appears
dramatically slashed midway through its course.
Elsewhere in the image the view is scattered with much closer stars
and more distant galaxies that happen to lie in the same direction.
 SN 1999em is a core-collapse supernova classified
more precisely as a Type IIp. The “p” stands for plateau, meaning
supernovae of this type remain bright (on a plateau) for a relatively
long period of time after maximum brightness.
ESO is the foremost intergovernmental
astronomy organisation in Europe and the world’s most productive
ground-based astronomical observatory by far. It is supported by 15
countries: Austria, Belgium, Brazil, the Czech Republic, Denmark,
France, Finland, Germany, Italy, the Netherlands, Portugal, Spain,
Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious
programme focused on the design, construction and operation of powerful
ground-based observing facilities enabling astronomers to make
important scientific discoveries. ESO also plays a leading role in
promoting and organising cooperation in astronomical research. ESO
operates three unique world-class observing sites in Chile: La Silla,
Paranal and Chajnantor. At Paranal, ESO operates the Very Large
Telescope, the world’s most advanced visible-light astronomical
observatory and two survey telescopes. VISTA works in the infrared and
is the world’s largest survey telescope and the VLT Survey Telescope is
the largest telescope designed to exclusively survey the skies in
visible light. ESO is the European partner of a revolutionary
astronomical telescope ALMA, the largest astronomical project in
existence. ESO is currently planning the 39-metre European Extremely
Large optical/near-infrared Telescope, the E-ELT, which will become “the
world’s biggest eye on the sky”.