Dark energy study releases

first insights

14 June 2023

The night sky above Kitt Peak National Observatory

The Mayall 4-Meter Telescope, home to the Dark Energy Spectroscopic Instrument (DESI), seen at night at Kitt Peak National Observatory in Arizona. Credit: LBL/Marilyn Sargent.

The Mayall 4-Meter Telescope, home to the Dark Energy Spectroscopic Instrument (DESI), seen at night at Kitt Peak National Observatory in Arizona. Credit: LBL/Marilyn Sargent.

Understanding the mysterious force behind the expanding universe is a step closer with the first tranche of data released from the Dark Energy Spectroscopic Instrument (DESI).

University of Queensland astrophysicist Dr Rossana Ruggeri is part of the team using DESI, the most powerful apparatus for photographing light ranges in the world.

A long-exposure night sky shot of the stars above the telescope

Star trails take shape around the 14-story Mayall Telescope dome in this long-exposure image. Credit: P. Marenfeld and NOAO/AURA/NSF.

Star trails take shape around the 14-story Mayall Telescope dome in this long-exposure image. Credit: P. Marenfeld and NOAO/AURA/NSF.

“The instrument is able to measure light from more than 100,000 galaxies in one night,” Dr Ruggeri said.

“It uses 5,000 robotic positioners to move optical fibres that capture light from objects millions or billions of light-years away.

“That light tells researchers how far away an object is, helping them to build a three-dimensional cosmic map.

An array of DESI robotic positioners, each equipped with a fibre-optic cable that will gather light from distant galaxies and other space objects. Credit: LBL.

An array of DESI robotic positioners, each equipped with a fibre-optic cable that will gather light from distant galaxies and other space objects. Credit: LBL.

“As the universe expands, it stretches light’s wavelength, making the light appear redder – a phenomenon known as redshift – and the further away the galaxy, the bigger the redshift.

“DESI specialises in collecting redshifts that can then be used to solve some of astrophysics’ biggest puzzles: what dark energy is and how it has changed throughout the universe’s history.”

Star trails captured with long-exposure photography at Kitt Peak National Observatory

Star trails take shape around Kitt Peak National Observatory in this long-exposure image. The 4-meter Mayall telescope building, at right, houses DESI. Credit: P. Marenfeld and NOAO/AURA/NSF

A view of the interior of the Mayall Telescope at Kitt Peak National Observatory

A view of the interior of the Mayall Telescope at Kitt Peak National Observatory. Credit: Marilyn Chung/Berkeley Lab

Stu Harris facing the DESI focal plane

Stu Harris of Lawrence Berkeley National Laboratory works on the assembly of a DESI focal plane. Credit: LBL/Marilyn Chung

Star trails captured with long-exposure photography at Kitt Peak National Observatory

Star trails take shape around Kitt Peak National Observatory in this long-exposure image. The 4-meter Mayall telescope building, at right, houses DESI. Credit: P. Marenfeld and NOAO/AURA/NSF

A view of the interior of the Mayall Telescope at Kitt Peak National Observatory

A view of the interior of the Mayall Telescope at Kitt Peak National Observatory. Credit: Marilyn Chung/Berkeley Lab

Stu Harris facing the DESI focal plane

Stu Harris of Lawrence Berkeley National Laboratory works on the assembly of a DESI focal plane. Credit: LBL/Marilyn Chung

The Lawrence Berkeley National Laboratory operate the instrument, which is located in Kitt Peak, Arizona.

More than 3,500 exposures were taken over six months during the experiment’s survey validation phase, creating 80 terabytes of initial data.

Dr Ruggeri and UQ colleagues including Dr Cullan Howlett, Dr Khaled Said and Professor Tamara Davis, play leading roles ensuring data quality, studying how gravity bends the path of light, and observing how galaxies move and cluster.

The UQ team said that DESI had already made two interesting discoveries – evidence of a mass migration of stars into the Andromeda galaxy, and incredibly distant quasars, which are the extremely bright and active supermassive black holes sometimes found at the centre of galaxies.

A tall white observatory with a rounded roof on a hill under a bright blue sky

Kitt Peak National Observatory on Tuesday in Tucson, Arizona. Credit: LBL/Marilyn Sargent

Kitt Peak National Observatory on Tuesday in Tucson, Arizona. Credit: LBL/Marilyn Sargent

A collection of fiber-optic connections

A collection of robotic fiber-optic positioners (at right) is assembled into the holes of a focal plane petal at Lawrence Berkeley National Laboratory. The positioners are wired to power supplies and electronic circuit boards. Credit: LBL/Marilyn Chung

Parker Fagrelius, a woman with medium-length brown hair, looking into ProtoDESI

Parker Fagrelius, a UC Berkeley graduate student in the Physics Department, working on ProtoDESI, a pathfinding instrument for the Dark Energy Spectroscopic Instrument. Credit: LBL/Paul Mueller.

A collection of fiber-optic connections

A collection of robotic fiber-optic positioners (at right) is assembled into the holes of a focal plane petal at Lawrence Berkeley National Laboratory. The positioners are wired to power supplies and electronic circuit boards. Credit: LBL/Marilyn Chung

Parker Fagrelius, a woman with medium-length brown hair, looking into ProtoDESI

Parker Fagrelius, a UC Berkeley graduate student in the Physics Department, working on ProtoDESI, a pathfinding instrument for the Dark Energy Spectroscopic Instrument. Credit: LBL/Paul Mueller.

UQ’s Professor Tamara Davis said that the initial discoveries were thrilling, but there was more to discover.

“DESI is currently two years into its five-year run and ahead of schedule on its quest to collect more than 40 million redshifts,” Professor Davis said.

“The survey has already catalogued more than 15 million galaxies in its science run and is adding more than a million per month.

“There’s plenty of data yet to come from the experiment, and it’s fantastic that UQ can be part of answering some of the most fundamental questions about our universe.”

The DESI early data release is now available online and images and videos are available from the Berkeley Lab website.

DESI is supported by the DOE Office of Science and the National Energy Research Scientific Computing Center, a DOE Office of Science user facility. Additional support for DESI is provided by the US National Science Foundation, the Science and Technologies Facilities Council of the United Kingdom, the Gordon and Betty Moore Foundation, the Heising-Simons Foundation, the French Alternative Energies and Atomic Energy Commission (CEA), the National Council of Science and Technology of Mexico, the Ministry of Science and Innovation of Spain, and DESI member institutions.

The DESI collaboration is honoured to be permitted to conduct scientific research on Iolkam Du’ag (Kitt Peak), a mountain with particular significance to the Tohono O’odham Nation.

Media: Dr Rossana Ruggeri, r.ruggeri@uq.edu.au, +61 450 735 109; Professor Tamara Davis, tamarad@physics.uq.edu.au, +61 432 526 989; Faculty of Science Media, science.media@uq.edu.au, +61 438 162 687.

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