Taken with the HAWK-I instrument on ESO’s Very Large Telescope in the Chilean Atacama Desert, this stunning image shows the Milky Way’s central region with an angular resolution of 0.2 arcseconds. This means the level of detail picked up by HAWK-I is roughly equivalent to seeing a football (soccer ball) in Zurich from Munich, where ESO’s headquarters are located. The image combines observations in three different wavelength bands. The team used the broadband filters J (centred at 1250 nanometres, in blue), H (centred at 1635 nanometres, in green), and Ks (centred at 2150 nanometres, in red), to cover the near infrared region of the electromagnetic spectrum. By observing in this range of wavelengths, HAWK-I can peer through the dust, allowing it to see certain stars in the central region of our galaxy that would otherwise be hidden.
Thanks to the latest generation of sophisticated telescopes, astronomers are learning things a great deal about our Universe. The improved resolution and observational power of these instruments also allow astronomers to address previously unanswered questions. Many of these telescopes can be found in the Atacama Desert in Chile, where atmospheric interference is minimal and the cosmos can be seen with greater clarity.
It is here that the European Southern Observatory (ESO) maintains many observatories, not the least of which is the Paranal Observatory where the Very Large Telescope (VLT) resides. Recently, an international team of astronomers used the VLT to study the center of the Milky Way and observed evidence of ancient starbursts. These indicate that the central region of our galaxy experienced an intense period of star birth in the past.
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. Credit: ESO
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Just like its ornithological namesake, the HAWK-I imager on the Very Large Telescope uses its piercing eyesight to hunt down its prey. But the High-Acuity Wide-field K-band Imager draws on its infrared vision to provide new insights into the spiral structures of galaxies. Today, ESO released six stunning new images of bright galaxies, showing exquisite detail with a clarity that is only possible by observing in the infrared.
Usually, dust in the arms of spiral galaxies blocks out much of the detail from our view, but observing in infrared light, much of the obscuring dust becomes transparent to its detectors. Compared to another VLT infrared camera called 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 greater sensitivity to faint infrared radiation.
The six galaxies are part of a study of spiral structure led by Preben Grosbøl at ESO. Because HAWK-I can study galaxies stripped bare of the confusing effects of dust and glowing gas it is ideal for studying the vast numbers of stars that make up spiral arms, as well as helping astronomers to understand the complex and subtle ways in which the stars in these systems form into such perfect spiral patterns.
NGC 5247. Credit: ESO
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 zodiacal constellation of Virgo (the Maiden).
Messier 100, also known as NGC 4321. Credit: ESO
The galaxy in the second image is Messier 100, also known as NGC 4321, which lies about 55 million light-years from Earth in the Virgo Cluster of galaxies. It is an example of a “grand design” spiral galaxy — a class of galaxies with very prominent and well-defined spiral arms.
NGC 1300. Credit: ESO
The third image is of NGC 1300, a spiral galaxy with arms extending from the ends of a 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, in the constellation of Eridanus (the River).
NGC 4030. Credit: ESO
The spiral galaxy in the fourth image, NGC 4030, lies about 75 million light-years from Earth, in the constellation of Virgo.
NGC 2997. Credit: ESO
The fifth image, NGC 2997, is a spiral galaxy roughly 30 million light-years away in the constellation of Antlia. 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, of which the Milky Way is a member, is itself also part of the Local Supercluster.
NGC 1232. Credit: ESO
Last but not least, NGC 1232 is a beautiful galaxy some 65 million light-years away in the constellation of Eridanus (the River). The galaxy is classified as an intermediate spiral galaxy — somewhere between a barred and an unbarred spiral galaxy.
