Posted on by Matt Williams

The ESO Releases the Most Detailed Infrared Map of our Galaxy Ever Made

This collage highlights a small selection of regions of the Milky Way imaged as part of the most detailed infrared map ever of our galaxy. Here we see, from left to right and top to bottom: NGC 3576, NGC 6357, Messier 17, NGC 6188, Messier 22 and NGC 3603. All of them are clouds of gas and dust where stars are forming, except Messier 22, which is a very dense group of old stars. The images were captured with ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA) and its infrared camera VIRCAM. The gigantic map to which these images belong contains 1.5 billion objects. The data were gathered over the course of 13 years as part of the VISTA Variables in the Vía Láctea (VVV) survey and its companion project, the VVV eXtended survey (VVVX).

Despite decades of large-scale optical surveys, there are still mysteries about the Milky Way galaxy that astronomers are eager to resolve. This is particularly true of its internal structure and the core region, which is difficult to survey due to clouds of gas and dust in the interstellar medium (ISM). This material absorbs visible light, making fainter objects difficult to see in optical wavelengths. Luckily, advances in infrared astronomy have enabled surveys of the Milky Way that have revealed things that would otherwise remain invisible to us.

For more than 13 years, an international team of astronomers has been observing the Milky Way using the ESO’s 4.1-meter Visible and Infrared Survey Telescope for Astronomy (VISTA). In a recently published study, they announced the release of their final data product: a gigantic infrared map of the Milky Way containing more than 1.5 billion objects—the most detailed map our galaxy has ever created! With over 200,000 images and 500 terabytes of data, this map is also the largest observational project ever carried out with an ESO telescope.

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