Astrophysicists have released the largest map of the universe so far

Only after seven months, a huge team of scientists working with the spectroscopic instrument for dark energy have already mapped a larger section of space than all other 3D research combined. And with only 10 percent of their five-year mission complete, much remains to be done.

DESI, pronounced as Desi Arnaz, has unveiled a spectacular space network of more than 7.5 million galaxies and will scan up to 40 million. The instrument is funded by the US Department of Energy and is installed in the 4-meter telescope Nicholas U. Mayall at the Kitt Peak National Observatory near Tucson, Arizona. It measures the exact distances of galaxies from Earth and the light they emit in a range of wavelengths, achieving both quantity and quality. It will eventually cover about 8,000 square degrees, about 20 percent of the sky. The science of data analysis is yet to come, but it will help astrophysicists in particular as they study how the universe is expanding.

“It’s really a fantastic adventure. We managed to continue despite the pandemic. We had to close for a few months and then we adapted, “said Julien Guy, a DESI scientist at the Lawrence Berkeley National Laboratory, the leading institution for collaboration. Now monitoring and data processing are mostly automated; every morning, scientists receive data on about 100,000 galaxies collected overnight, he said.

“It’s amazing how well this instrument works and how well it’s designed to come out and get the distances to these galaxies. It’s an incredibly efficient machine for collecting them in a way that would have been mind-boggling even two decades ago, “said Jason Rhodes, a researcher at the Pasadena Jet Propulsion Laboratory who works on space telescopes to map galaxies in the early universe.

Section through the 3-D map of galaxies from the completed digital study of the Sloan sky (left) and from the first few months of the Dark Energy Spectroscopy Instrument (DESI; right). The earth is in the center, with the most distant galaxies drawn at distances of 10 billion light years. Each point represents a galaxy. This preliminary version of the DESI map shows only 400,000 of the 35 million galaxies that will be on the final map. Courtesy of D. Schlegel / Berkeley Lab, using data from DESI

DESI actually consists of several devices installed in the 14-storey dome of the telescope. The round focal plane is located near the top and consists of 10 wedge-shaped petals, each with 500 small robots. They are what galactic mapping of the instrument allows: These 5,000 robotic pencil-sized motors position optical fibers that need to be precisely positioned up to 10 microns – less than the thickness of a human hair. This allows the tool to collect accurate data on 5,000 galaxies at once. The telescope then headed to another area of ​​the night sky and began work on the next 5,000. In contrast, in one of DESI’s predecessors, the Sloan Digital Sky Survey, based on a telescope in southern New Mexico, scientists had to drill holes by hand. in a round aluminum plate in the focus of the telescope for each set of measurements, and they included some fibers for each individual galaxy they wanted to observe.

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