Six spectacular spiral galaxies seen in a clear new light in images from ESO's Very Large Telescope (VLT) at the Paranal Observatory in Chile. The pictures were taken in infrared light, using the impressive power of the HAWK-I camera to help astronomers understand how the remarkable spiral patterns in galaxies form and evolve. From left to right is the galaxy NGC 5427, Messier 100 (NGC 4321), NGC 1300, NGC 4030, NGC 2997 and NGC 1232. (Credit: ESO / P. Grosbøl)
Six spectacular spiral galaxies are seen in a clear new light in images from ESO's Very Large Telescope (VLT) at the Paranal Observatory in Chile. The pictures were taken in infrared light, using the impressive power of the HAWK-I camera, and will help astronomers understand how the remarkable spiral patterns in galaxies form and evolve.
HAWK-I [1] is one of the newest and most powerful cameras on ESO's Very Large Telescope (VLT). It is sensitive to infrared light, which means that a lot of the dust cover on the arm of a spiral galaxy 'be transparent to the detector. Compared with before, and is still widely used, VLT infrared camera ISAAC, HAWK-I has sixteen times as many pixels to cover a much larger area of sky in one shot and, by using newer technology than ISAAC, it has a sensitivity greater faint infrared radiation [2]. Because HAWK-I can study galaxies stripped bare confusing effects of dust and glowing gas it is ideal for studying a large number of stars that make up spiral arms.
The six galaxies are part of a study of spiral structure led by Preben Grosbøl at ESO. This data was obtained to help understand the complex and subtle ways in which the stars in these systems form into such perfect spiral patterns.
The first image shows NGC 5247, a spiral galaxy dominated by two huge arms, located 60-70 million light years away. The galaxy lies face-on towards Earth, thus providing an excellent view of its pinwheel structure. It lies in the constellation of the zodiac Virgo (Maiden).
Galaxies in the second image is Messier 100, also known as NGC 4321, is found in the18th century. This is a good example of a galaxy "grand design" spiral - a class of galaxies with spiral arms are very prominent and well defined. About 55 million light-years from Earth, Messier 100 is part of the Virgo Cluster of galaxies and lies in the constellation Coma Berenices (Berenice Hair, named after the ancient Egyptian queen Berenice II).
The third image is of NGC 1300, a spiral galaxy with arms extending from the ends spectacularly prominent central bar. It is considered a prototypical example of barred spiral galaxies and lies at a distance of about 65 million light-years away in the constellation Eridanus (the River).
Spiral galaxy in the fourth image, NGC 4030, located about 75 million light years from Earth, in the constellation Virgo. In 2007 Takao Doi, Japanese astronaut who doubles as an amateur astronomer, saw a supernova - an exploding star almost as bright short of its host galaxy - going in the galaxy.
The fifth image, NGC 2997, is a spiral galaxy about 30 million light-years away in the constellation Antlia (Water Pump). NGC 2997 is the brightest member of a group of galaxies of the same name in the local supercluster of galaxies. Our own local group, the Milky Way is a member, is itself also part of the Local supercluster.
Last but not least, NGC 1232 is a beautiful galaxy some 65 million light-years away in the constellation Eridanus (the River). The galaxy is classified as an intermediate spiral galaxy - somewhere between a barred and unbarred spiral galaxy. A small image of the galaxy and the companion galaxy NGC 1232A in visible light was one of the first produced by the VLT (eso9845). HAWK-I has now returned to NGC 1232 to show a different view of it at infrared wavelengths.
As this galactic gallery explains, HAWK-I lets us see the spiral structures in six bright galaxies in exquisite detail and with a clarity that is only possible by observing in the infrared.
Note
[1] HAWK-I stands for High-Acuity Wide-field Imager K-band.
[2] Further information about the VLT instruments can be found at: http://www.eso.org/public/teles-instr/vlt/vlt-instr.html.
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