UK-Designed and Built VISTA Telescope Views the Sculptor Galaxy

A spectacular new image of the Sculptor Galaxy (a galaxy currently undergoing a period of intense star formation),has been captured by the UK-designed and built ESO VISTA telescope, the world’s largest survey telescope with a mirror over 4 metres in diameter. The image, taken at the Paranal Observatory in the Chilean Atacama Desert as part of its first major observational campaign, provides new information on the history and development of the galaxy.

The Sculptor Galaxy (NGC 253) lies about 13 million lightyears away and is the brightest member of a small collection of galaxies called the Sculptor Group, one of the closest such groupings to our own Local Group of galaxies. It was discovered by Caroline Herschel from England in 1783 and is prominent enough to be seen with good binoculars but dust obscures the view of many parts of the galaxy; but because VISTA (Visible and Infrared Survey Telescope for Astronomy) works at infrared wavelengths it can see right through the dust that is such a prominent feature of the Sculptor Galaxy.

The stunning image shows the galaxy is almost edge on, with the spiral arms clearly visible in the outer parts, along with a bright core at its centre. It also reveals huge numbers of cooler stars that are barely detectable with visible-light telescopes.

Astronomers are studying the numerous cool red giant stars in the halo that surrounds the Sculptor Galaxy, measuring the composition of some of NGC 253’s small dwarf satellite galaxies, and searching for as yet

undiscovered new objects such as globular clusters and ultra-compact dwarf galaxies that would otherwise be invisible without the dust-penetrating VISTA infrared images. Using the unique VISTA data astronomers plan to map how the galaxy formed and evolved.

Professor Richard Holdaway, Director, Space Science and Technology Department at STFC’s Rutherford Appleton Laboratory where the camera for the telescope was part-built, said: “The level of detail shown in images from VISTA is clearly unprecedented. Together with further observations by other telescopes, including ESO’s Very Large Telescope (VLT) located on the next mountain peak, astronomers are able to build the clearest pictures to date of the Sculptor Galaxy, telling us more about its history and the way it formed.”