Scientists release the largest 2D map of the Universe: 4 billion objects, 5.6 trillion pixels

Scientists from Lawrence Berkeley National Laboratory and NSF NOIRLab have released Legacy Surveys, the largest 2D map of the Universe ever created. The atlas covers 75% of the celestial sphere, features nearly 4 billion cosmic objects, and boasts a resolution of 5.6 trillion pixels.

The project was led by David Schlegel from Berkeley Lab and Arjun Dey from NSF NOIRLab. More than 160 researchers contributed to the effort, and a dedicated team of 20 specialists compiled the final dataset. They merged 263,407 individual images captured over 2,285 nights of observation.

The data came from three ground-based surveys: the Dark Energy Camera Legacy Survey (DECaLS) at Cerro Tololo Inter-American Observatory in Chile, the Mayall z-band Legacy Survey (MzLS) at Kitt Peak National Observatory, and the Beijing-Arizona Sky Survey (BASS) at Steward Observatory in Arizona. Infrared observations from NASA's WISE satellite were also used to enhance the dataset.

Processing such a massive volume of data required the Perlmutter supercomputer at the National Energy Research Scientific Computing Center (NERSC). It took one year to develop the code and another eight weeks to compute the images.

The primary purpose of the map is to serve as a 2D foundation for 3D mapping of the Universe. Legacy Surveys directly supports the Dark Energy Spectroscopic Instrument (DESI), which has been measuring the spectra of millions of galaxies and quasars since 2021. DESI aims to build the most detailed 3D map ever and refine our understanding of dark energy.