Dark energy instrument receives funding from Department of Energy

In the ongoing effort to understand the structure of the universe, the recent federal approval of the Dark Energy Spectroscopic Instrument (DESI) has ensured a promising next step. According to DESI’s website, DESI “will measure the effect of dark energy on the expansion of the universe and obtain optical spectra for tens of millions of galaxies and quasars, constructing a 3-dimensional map spanning the nearby universe to 10 billion light years.” The receipt of Critical Decision-2 funding from the Department of Energy has secured funding of the project for the next ten years, allowing scientists to gather information about the nature of dark matter, dark energy, and the expansion of the universe.

Shirley Ho, Assistant Professor of Physics and a member of Carnegie Mellon’s McWilliams Center for Cosmology, is the co-chair of the project’s Galaxy and Quasar Clustering Working Group. In this capacity, Ho leads the preparation and analysis of data received from the telescope. Over two hundred researchers from around the world will work alongside Ho.

“DESI will push science further than we have ever gone before,” Ho said. “We will get a map of the universe from when the universe was very young, about one-seventh of its current age. This will help us to better understand dark matter, dark energy and other mysterious things in our universe.” Among other questions, Ho and her colleagues hope to gain a better understanding of the accelerating expansion of the universe, an observation not in line with Einstein’s theory of gravity.

Beyond mapping the universe, DESI will provide valuable information that will allow researchers to envision baryon acoustic oscillations, which are density fluctuations in the early universe. DESI will also provide insight into the standard model of particle physics by focusing on the total mass of neutrinos in the universe.

DESI is set to be mounted on the Mayall Telescope, which is operated by the National Optical Astronomy Observatory and is located in Tucson, Arizona. In order to meet DESI’s operational requirements, the Mayall telescope will be augmented with new, intricate glass lenses that will help focus light onto DESI’s focal plane. 5,000 robotic arms will position optical fibres so that they capture light from a specific point of interest, such as a galaxy or quasar. With this sophisticated tool, researchers aim to measure spectra of over 30 million galaxies and quasars. The Baryon Oscillation Spectroscopic Survey of the Sloan Digital Sky Survey, DESI’s predecessor, was only able to measure approximately one tenth as many objects.

With funding in place, the first measurements from the Mayall 4-meter telescope in Tucson, Arizona are expected to begin in 2018. Dark matter and energy are enigmatic quantities that continue to evade the understanding of modern science, but DESI is set to begin a decade of unprecedented exploration, which could hopefully lead to answers to some of our questions.