The 3D map of the DESI universe already includes two million objects

2023-06-14 12:42:13

DESI is making a 3D map of the universe to better understand dark energy. – DAVID KIRKBY/DESI COLLABORATION

MADRID, 14 Jun. (EUROPA PRESS) –

The first batch of data from the DESI (Dark Energy Spectroscopic Instrument), with almost two million objects, it is now available for researchers to extract.

Taken during the “survey validation” phase of the experiment, the data includes distant galaxies and quasars, as well as stars in our own Milky Way, informa el LBNL (Lawrence Berkeley National Laboratory)which operates the instrument.

To study dark energy, the mysterious force behind the accelerating expansion of our universe, scientists are using DESI to create a 3D map of the universe with more than 40 million galaxies, quasars and stars.

The 80 terabyte data set comes from 2,480 exposures taken over six months during the “survey validation” phase of the experiment in 2020 and 2021. In this period between turning on the instrument and beginning the official scientific run, the researchers made sure that his plan to use the telescope would meet his scientific objectives, for example, checking how long it took to observe galaxies of different brightness and validating the selection of stars and galaxies to observe.

The collaboration also published a number of papers related to early data release, including early measurements of galaxy clustering, rare object surveys, and descriptions of the instrument and survey operations. The new papers build on DESI’s first measurement of the cosmological distance scale that was published in April, which used the first two months of routine survey data (not included in the initial data release). and also showcased DESI’s ability to achieve its design goals.

DESI uses 5,000 robotic positioners to move optical fibers that capture light from objects millions or billions of light-years away. It is the most powerful multi-object survey spectrograph in the world, capable of measuring the light of more than 100,000 galaxies in one night. That light tells researchers how far away an object is, building a 3D cosmic map.

Part of DESI’s survey validation included the “One Percent Survey” displayed on this tour. The researchers took detailed images in 20 different directions in the sky, creating a 3D map of 700,000 objects and covering about 1% of the total volume that DESI will study. With the instrument and survey plan successfully tested, DESI’s main survey is now filling in the gaps between those observations.