An all-seeing eye

Astronomers spend their time gazing out into the Universe — and occasionally the Universe seems to peer right back! This image, a composite of data from the Atacama Large Millimeter/submillimeter Array (ALMA) and the NASA/ESA Hubble Space Telescope, shows a very rare cosmic sight: a pair of interacting galaxies that have taken on an ocular structure.

As the name suggests, some types of grazing encounters between galaxies create shapes that resemble the human eye. While galaxy collisions of this type are not uncommon, only a few galaxies with eye-like, or ocular, structures have been observed. The paucity of these features is likely due to their very ephemeral nature — ocular structures like these tend to only last for several tens of millions of years, which is merely the blink of an eye in a galactic lifetime.

These two galaxies are named IC 2163 (left) and NGC 2207 (right) — IC 2163 displays the ocular structure in this image. The duo lies approximately 114 million light-years from Earth in the direction of the constellation of Canis Major (The Greater Dog).

The galaxies have brushed past each other — scraping the outer edges of their spiral arms —with IC 2163 passing behind NGC 2207. This glancing collision triggered a tsunami of stars and gas in IC 2163, with material in the outer portions of the disc of the galaxy travelling inwards This colossal wave of material decelerated rapidly moving from the outer to the inner edge of the eyelids and crashed midway through the galaxy’s disc, producing dazzling ribbons of intense star formation and compressed ridges of gas and dust that resemble a pair of cosmic “eyelids”.

Notes

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

Link

Credit:

ALMA (ESO/NAOJ/NRAO)/M. Kaufman & the NASA/ESA Hubble Space Telescope

About the Image

Id:potw1645a
Type:Observation
Release date:7 November 2016, 06:00
Size:3298 x 1815 px

About the Object

Name:IC 2163, NGC 2207
Type:Local Universe : Galaxy : Type : Interacting
Distance:110 million light years
Constellation:Canis Major
Category:Galaxies

Image Formats

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1.4 MB
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Coordinates

Position (RA):6 16 23.45
Position (Dec):-21° 22' 22.28"
Field of view:3.98 x 2.19 arcminutes
Orientation:North is 11.2° right of vertical

Colours & filters

BandWavelengthTelescope
Optical
V
555 nmHubble Space Telescope
WFPC2
Optical
I
814 nmHubble Space Telescope
WFPC2
Optical
U
336 nmHubble Space Telescope
WFPC2
Optical
B
439 nmHubble Space Telescope
WFPC2
Millimeter
CO
Atacama Large Millimeter/submillimeter Array

 

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