One million galaxies mapped per month: DESI already breaks all records

The Dark Energy Spectroscopic Instrument (DESI) has already broken all records six months after it went into operation and has already created the largest, most detailed map of the universe. This was announced by those responsible for the instrument installed at Kitt Peak National Observatory in Arizona. Over 7.5 million galaxies have already been mapped and over a million are being added each month. Originally there was talk of 30 million galaxies that the instrument would map in total, but those responsible are now talking of 35 million. After the end of the observation campaign in 2026, the data set should enable cosmological and astrophysical research that has not been possible so far.

The primary task of DESI is to collect spectra from tens of millions of galaxies, covering around a third of the night sky. From the spectra, researchers can not only deduce the chemical composition of the radiating objects, but also their relative distance and proper motion, depending on how far it is red-shifted. The goal is the largest map of the expanding universe. Thanks to robot-controlled glass fibers, the instrument can simultaneously capture the spectra of 5,000 galaxies and measure up to 150,000 objects on a good night. So far, that’s what makes it so quiet and continuous that the monitoring shifts are considered “boring,” says Ohio State University physicist Klaus Honscheid.

Even though DESI has only done about 10 percent of its work, the large-scale structures in which galaxies are arranged can already be seen on the collected data. Huge clusters of galaxies, elongated structures (filaments) and empty areas (voids) can be seen in the visualizations that have now been published.

A three-dimensional cutout

(Bild: D. Schlegel/Berkeley Lab using data from DESI)

Other graphics make it clear, how much more comprehensive the current DESI atlas is compared to the most complete so far, the Sloan Digital Sky Survey. DESI’s data will go back 11 billion years and will not only help in researching the history of the cosmos and the nature of the mysterious dark energy. They are already helping, for example, to explore quasars, active nuclei of galaxies that glow particularly brightly.

A small but particularly dense section of sky…
(Bild: DESI collaboration and DESI Legacy Imaging Surveys)


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