It's taken 13 years, but astronomers have produced the most detailed infrared map of the Milky Way ever made.
Containing over 1.5 billion objects and comprising 500 terrabytes of data, the team behind the map say it's an unprecedented leap forward in our understanding of the Milky Way.
“We made so many discoveries, we have changed the view of our Galaxy forever,” says Dante Minniti, an astrophysicist at Universidad Andrés Bello in Chile who led the project.
More on the Milky Way
Making a Milky Way map
To make the map, the team used the European Southern Observatory’s VISTA telescope, located in the pristine stargazing location of Chile's Atacama Desert.
Dry, clear and far from artificial light pollution, it's the perfect ground-based location to create a map of this kind, the largest observational project ever carried out with an ESO telescope.
200,000 images were captured by ESO’s VISTA to produce the infrared Milky Way map.
VISTA's core objective is mapping large areas of the sky, and its infrared camera VIRCAM can see through cosmic dust and gas to get to the heart of our galaxy's biggest secrets.
It can detect radiation from the Milky Way’s many hideaway regions, giving astronomers a view of our galactic neighbourhood that would otherwise be hidden from the human eye.
What the VISTA Milky Way map shows
Consider how big and bright the full Moon appears in our sky. The VISTA Milky Way map covers an area of the sky equivalent to 8,600 full Moons.
It contains 10 times more objects than a 2012 map released by the same team: a wealth of celestial targets such as:
- Newborn stars, often embedded in dusty cocoons
- Globular clusters: ancient, dense groupings of stars
- Failed stars known as brown dwarfs
- Free-floating, rogue planets that don’t orbit a star
How they did it
Observations to produce the infrared Milky Way map began back in 2010 and ended in the first half of 2023.
It took a total of 420 nights and the team used VISTA to observe the same patch of sky numerous times.
They were able to determine the locations of celestial objects, track how they move and whether their brightness changes.
Stars whose luminosity changes periodically can be used for measuring distance in the Universe, and are known as 'standard candles'.
The map has given astronomers a 3D view of the inner regions of the Milky Way, previously hidden by dust.
And they were able to track stars that have been flung out of the centre of the Milky Way via gravitational interactions with the galaxy's central supermassive black hole.
"The project was a monumental effort, made possible because we were surrounded by a great team,” says Roberto Saito, an astrophysicist at the Universidade Federal de Santa Catarina in Brazil and lead author of the paper published in Astronomy & Astrophysics.
Read the full paper at aanda.org/articles/aa/full_html/2024/09/aa50584-24/aa50584-24.html
