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Clear view of a classic spiral
Posted: 20 May 2010

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A new infrared image of nearby galaxy M83 has been taken by the HAWK-I instrument on ESO's Very Large Telescope at the Paranal Observatory in Chile, revealing a whole host of stars that are otherwise invisible.

Comparison of M83 seen in visible light (right, taken by the Wide Field Imager on the 2.2-metre MPG/ESO telescope at La Silla in Chile) and infrared (left, as seen by HAWK-I). In the infrared, the dust that obscures many stars becomes nearly transparent, making the spiral arms less dramatic, but revealing a whole host of new stars that are otherwise invisible. Image: ESO/M. Gieles.

M83 resides 15 million light years away from the Earth in the constellation of Hydra and spans 40,000 light years. Although this may sound large, it is just 40 percent the size of the Milky Way, but its spiral form and central bar is quite similar to our home Galaxy.

The galaxy is also a favourite for supernova hunters and over the last century six supernovae explosions – the dramatic end point for stars that have exhausted their nuclear fuel – have been observed there.

Highlights of M83 as seen by HAWK-I. As well as showing the structure of the galaxy without the obscuring effect of dust, huge numbers of stars within the galaxy are revealed. Image: ESO/M. Gieles.

Now, M83 has been observed by the HAWK-I (High-Acuity Wide-field K-band Imager) camera in the infrared, which sees through the dust that obscures visible light observations, revealing finer details of the galaxy's structure and stellar population. This clear view is especially important for studies of clusters of young stars; the bright gas that surrounds these stellar newborns is less prominent at infrared wavelengths, allowing astronomers to get a closer look.