An international collaboration of astronomers recently released the most accurate map yet of all the matter in the universe, to help understand dark matter, and now it’s accompanied by the largest two-dimensional map of the entire sky, which d could help in the study of dark energy. A data release from the Dark Energy Spectroscopic Instrument Legacy Imaging Survey (DESI) shared the results from six years of scanning nearly half the sky, yielding a total of one petabyte of data from three different telescopes.
The reason such large-scale data is needed to study dark energy and dark matter is that these can only be detected because of their effects on ordinary matter – so researchers look at many galaxies to keep track of how these unseen forces are contributing to the mass. or affecting the interaction between galaxies. This particular map was created to help scientists identify 40 million target galaxies that will be studied as part of the DESI Spectroscopic Survey.
To make the map as comprehensive as possible, the researchers included data taken in the near-infrared wavelength as well as the visible light wavelength. That is important because the light from distant galaxies appears to be reshifted, or shifted towards the red end of the spectrum, due to the expansion of the universe. “Near-infrared wavelength data from the Legacy Survey will allow us to better calculate the redshifts of distant galaxies, or the amount of time it took light from those galaxies to reach Earth,” explained one of the researchers, Alfredo Zenteno from the NSF’s NOIRLab, in a statement.
The map should also be useful to astronomers in other fields, such as those looking at radio or X-ray wavelengths, as it may help locate the sources of these other emissions.
“Anyone can use the survey data to explore the sky and make discoveries,” said Arjun Dey, an astronomer with NSF’s NOIRLab. “In my opinion it is this ease of access that made this survey so impactful. We hope that in a few years the Legacy Surveys will have the most complete map of the whole sky, and provide a treasure trove for scientists long into the future.”