Astronomy

ESO: New infrared images clear up the Small Magellanic Cloud

The latest report from ESO (European Southern Observatory):

VISTA Peeks Through the Small Magellanic Cloud’s Dusty Veil

The Small Magellanic Cloud galaxy is a striking feature of the southern sky even to the unaided eye. But visible-light telescopes cannot get a really clear view of what is in the galaxy because of obscuring clouds of interstellar dust. VISTA’s infrared capabilities have now allowed astronomers to see the myriad of stars in this neighbouring galaxy much more clearly than ever before. The result is this record-breaking image — the biggest infrared image ever taken of the Small Magellanic Cloud — with the whole frame filled with millions of stars.

The Small Magellanic Cloud (SMC) galaxy is a striking feature of the southern sky even to the unaided eye. But visible-light telescopes cannot get a really clear view of what is in the galaxy because of obscuring clouds of interstellar dust. VISTA’s infrared capabilities have now allowed astronomers to see the myriad of stars in this neighbouring galaxy much more clearly than ever before. The result is this record-breaking image — the biggest infrared image ever taken of the Small Magellanic Cloud — with the whole frame filled with millions of stars. As well as the SMC itself this very wide-field image reveals many background galaxies and several star clusters, including the very bright 47 Tucanae globular cluster at the right of the picture. [Larger versions.]
The Small Magellanic Cloud (SMC) is a dwarf galaxy, the more petite twin of the Large Magellanic Cloud (LMC). They are two of our closest galaxy neighbours in space — the SMC lies about 200 000 light-years away, just a twelfth of the distance to the more famous Andromeda Galaxy.  Both are also rather peculiarly shaped, as a result of interactions with one another and with the Milky Way itself.

This video takes a quick look at a remarkable new image from ESO’s VISTA survey telescope at the Paranal Observatory in Chile. The huge picture shows one of our neighbouring galaxies, the Small Magellanic Cloud, in remarkable detail and in infrared light.

Their relative proximity to Earth makes the Magellanic Clouds ideal candidates for studying how stars form and evolve. However, while the distribution and history of star formation in these dwarf galaxies were known to be complex, one of the biggest obstacles to obtaining clear observations of star formation in galaxies is interstellar dust. Enormous clouds of these tiny grains scatter and absorb some of the radiation emitted from the stars — especially visible light — limiting what can be seen by telescopes here on Earth. This is known as dust extinction.

These cutout images show a few of the highlights from a huge new infrared image of our neighbouring galaxy, the Small Magellanic Cloud, that was taken with the VISTA telescope at ESO’s Paranal Observatory. The lower-right panel shows the bright globular star cluster 47 Tucanae, which lies much closer to the Earth than the Small Magellanic Cloud. [Larger versions]
The SMC is full of dust, and the visible light emitted by its stars suffers significant extinction. Fortunately, not all electromagnetic radiation is equally affected by dust. Infrared radiation passes through interstellar dust much more easily than visible light, so by looking at the infrared light from a galaxy we can learn about the new stars forming within the clouds of dust and gas.

VISTA, the Visible and Infrared Survey Telescope, was designed to image infrared radiation. The VISTA Survey of the Magellanic Clouds (VMC) is focused on mapping the star formation history of the SMC and LMC, as well as mapping their three-dimensional structures. Millions of SMC stars have been imaged in the infrared thanks to the VMC, providing an unparalleled view almost unaffected by dust extinction.

The video sequence takes the viewer from a wide view of the southern skies deep into a small nearby galaxy, the Small Magellanic Cloud. The final close-up infrared views are from a very detailed huge image of the galaxy taken using ESO’s VISTA infrared survey telescope at the Paranal Observatory in Chile. Millions of stars and many star clusters and much more distant galaxies are visible. Credit: ESO/VISTA VMC/N. Risinger (skysurvey.org). Music: Astral electronic.

The whole frame of this massive image is filled with stars belonging to the Small Magellanic Cloud. It also includes thousands of background galaxies and several bright star clusters, including 47 Tucanae at the right of the picture, which lies much closer to the Earth than the SMC. The zoomable image will show you the SMC as you have never seen it before!

The wealth of new information in this 1.6 gigapixel image (43 223 x 38 236 pixels) has been analysed by an international team led by Stefano Rubele of the University of Padova. They have used cutting-edge stellar models to yield some surprising results.

This view compares a huge new infrared image of the Small Magellanic Cloud from ESO’s VISTA telescope to a more traditional view in visible light. By observing at longer infrared wavelengths VISTA can penetrate the dust clouds of this small neighbouring galaxy and reveal the stars much more clearly. Credit: ESO/VISTA VMC/Digitized Sky Survey 2. Music: Astral electronic. [Larger versions.]

The VMC has revealed that most of the stars within the SMC formed far more recently than those in larger neighbouring galaxies. This early result from the survey is just a taster of the new discoveries still to come, as the survey continues to fill in blind spots in our maps of the Magellanic Clouds.

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