It Took Astronomers 13 Years to Create the Biggest Infrared Map of the Milky Way

Astronomers using the European Southern Observatory’s (ESO) VISTA telescope have created and published a massive infrared map of the Milky Way galaxy containing more than 1.5 billion objects, the most detailed map of its kind ever.

The team used VISTA’s infrared camera, VIRCAM, over 13 years to create the map, collecting 500 terabytes of data. It’s the largest observational project ever conducted using an ESO telescope.

VIRCAM, a shortening of VISTA InfraREd CAMera, is a wide field camera. Each of the camera’s 67 million pixels covers 0.34 arcseconds. The massive camera weighs three tons and has 16 special detectors sensitive to infrared light from 0.9 to 1.2 μm.

“We made so many discoveries, we have changed the view of our Galaxy forever,” says project leader Dante Minniti, an astrophysicist at Universidad Andrés Bello in Chile. VISTA is located at ESO’s Paranal Observatory in Chile, a popular location for ground-based telescopes due to high elevations and favorable atmospheric conditions.

Thanks to its infrared capabilities, VIRCAM can see through dust and gas spread throughout the galaxy and see radiation that would otherwise be hidden in the far reaches of the Milky Way.

The massive dataset covers an area of the sky equivalent to 8,600 full Moons, per the ESO, and includes 10 times more objects than a similar map released by the same team in 2012. The new dataset includes “newborn stars, which are often embedded in dusty cocoons, and globular clusters — dense groups of millions of the oldest stars in the Milky Way.”

The observations, which began in 2010 and comprised 420 nights, hit the same patches of the night sky multiple times to get a detailed look at a diverse range of objects and monitor their movement and luminosity changes over time. The team charted stars whose brightness changes periodically as they can be used as a sort of cosmic ruler to measure distances, providing a 3D view of the inner regions of the Milky Way that were previously obscured by dust.

The new map includes data from the VISTA Variables in the Vía Láctea (VVV) survey and its companion project, the VVV eXtended (VVVX) survey. These two related surveys have resulted in over 300 scientific articles already. Vía Láctea is “Milky Way” in Latin, by the way.

“The project was a monumental effort, made possible because we were surrounded by a great team,” explains Roberto Saito, an astrophysicist at the Universidade Federal de Santa Catarina in Brazil and lead author of the paper published in Astronomy & Astrophysics.

The scientific work concerning the groundbreaking infrared map will continue for decades and will utterly reshape the scientific understanding of the Milky Way Galaxy and the Universe beyond.

Image credits: ESO/VVV Survey/VVVX Survey/D. Minniti. Acknowledgement: Ignacio Toledo