Hubble image of Arp 142
The area around merging galaxy duo Arp 142 (ground-based image)
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The NASA/ESA Hubble Space Telescope has
produced this vivid image of a pair of interacting galaxies known as Arp
142. When two galaxies stray too close to each other they begin to
interact, causing spectacular changes in both objects. In some cases the
two can merge — but in others, they are ripped apart.
Just below the centre of this image is the blue, twisted form of
galaxy NGC 2936, one of the two interacting galaxies that form Arp 142
in the constellation of Hydra. Nicknamed "the Penguin" or "the Porpoise"
by amateur astronomers, NGC 2936 used to be a standard spiral galaxy
before being torn apart by the gravity of its cosmic companion.
The remnants of its spiral structure can still be seen — the former
galactic bulge now forms the "eye" of the penguin, around which it is
still possible to see where the galaxy's pinwheeling arms once were.
These disrupted arms now shape the cosmic bird's "body" as bright
streaks of blue and red across the image. These streaks arch down
towards NGC 2936's nearby companion, the elliptical galaxy NGC 2937,
visible here as a bright white oval. The pair show an uncanny
resemblance to a penguin safeguarding its egg.
The effects of gravitational interaction between galaxies can be
devastating. The Arp 142 pair are close enough together to interact
violently, exchanging matter and causing havoc.
In the upper part of the image are two bright stars, both of which
lie in the foreground of the Arp 142 pair. One of these is surrounded by
a trail of sparkling blue material, which is actually another galaxy.
This galaxy is thought to be too far away to play a role in the
interaction — the same is true of the galaxies peppered around the body
of NGC 2936. In the background are the blue and red elongated shapes of
many other galaxies, which lie at vast distances from us — but which can
all be seen by the sharp eye of Hubble.
This pair of galaxies is named after the American astronomer Halton Arp, the creator of the Atlas of Peculiar Galaxies,
a catalogue of weirdly-shaped galaxies that was originally published in
1966. Arp compiled the catalogue in a bid to understand how galaxies
evolved and changed shape over time, something he felt to be poorly
understood. He chose his targets based on their strange appearances, but
astronomers later realised that many of the objects in Arp's catalogue
were in fact interacting and merging galaxies [1].
This image is a combination of visible and infrared light, created from data gathered by the NASA/ESA Hubble Space Telescope Wide Field Planetary Camera 3 (WFC3).
Notes
[1] The birth and evolution of various sets of merging galaxies was the subject of the book Cosmic Collisions – The Hubble Atlas of Merging Galaxies,
produced by Springer and the European Southern Observatory. The book is
illustrated with a range of stunning Hubble Space Telescope images.
More information
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Links
- Images of Hubble
- Cosmic Collisions – The Hubble Atlas of Merging Galaxies
- Hubble Heritage site
- NASA press release
Contacts
Nicky GuttridgeESA/Hubble
Garching, Germany
Tel: +49-89-3200-6855
Email: nguttrid@partner.eso.org
