DESI creates the largest three-dimensional map of the cosmos
The collaboration involves IEEC researchers at the Institute of Space Sciences (ICE-CSIC) and the Institute of Cosmos Sciences (ICCUB).
The Dark Energy Spectroscopic Instrument (DESI) has completed its first 7 months of observation, surpassing all previous three-dimensional galaxy mapping studies. After only 10% of the planned 5 years of observation, DESI has already succeeded in creating the largest and most detailed map of the Universe to date. The DESI collaboration involves researchers from the Institute of Space Studies of Catalonia (IEEC) at the Institute of Space Sciences (ICE-CSIC) and the Institute of Cosmos Sciences of the University of Barcelona (ICCUB).
Once the DESI project is completed, the three-dimensional map of galaxies created, which will have unprecedented detail, will help to study dark energy and contribute to a better understanding of the past and future of the Universe. This mapping will be essential for understanding the processes that regulate the formation and evolution of galaxies.
In the meantime, DESI's impressive technical performance and achievements to date are helping the scientific community to unlock the secrets of the most powerful light sources in the Universe. It has been able to recreate a highly detailed map of the distribution of galaxies in three dimensions, and to see their structure in filaments, clusters and empty areas. To do this, DESI requires incredibly detailed control of the 5000 new-generation robots that position the optical fibres that make up the instrument, so that their positions are correct to within 10 microns of error.
"With the telescope’s system of 5000 robotic fibres, we are increasing the cosmological precision to limits never seen before," says Santiago Serrano, IEEC researcher at ICE-CSIC, who has designed the instrument's autoguiding software. "The self-guiding systems have to help position the instrument so it can collect light from galaxies that are more than a billion light-years away. It is very gratifying to see that the work you have put into getting the instrument to point properly is helping to unravel the secrets of the Universe," he adds.
Three-dimensional axial computed tomography of the Universe made by DESI. Each coloured dot represents a galaxy, which in
turn is made up of 100 billion to 1 trillion stars. Gravity has grouped the galaxies into structures called "cosmic webs", with
dense clusters, filaments and voids (D. Schlegel/Berkeley Lab using data from DESI).
Studying the echoes of the Universe
That level of precision is necessary to achieve the mapping main task: collecting spectra of millions of galaxies, thus determining their position over more than a third of the entire sky. With a three-dimensional map of the Cosmos in hand, physicists will be able to trace clusters and superclusters of galaxies, structures that carry echoes of their initial formation, from when they were just waves in the primordial Cosmos. Detecting these ones will help to understand the physics of the first 10-32 seconds of the Universe's life and, thus, determine the history of its expansion.
But unveiling the fate of the Universe will have to wait until DESI has completed a larger part of its mapping. In the meantime, the instrument is already advancing our knowledge of the distant past, more than ten billion years ago, when galaxies were still young.
Some of DESI's data are being used to understand the behaviour of intermediate-mass black holes in small galaxies. All large galaxies, like our own, are thought to harbour massive black holes in their cores. But it is still unknown whether small galaxies also have their own (smaller) black holes.
Although such black holes are virtually impossible to discover, if they attract enough material they become easier to locate. As dust, gas and other materials fall into the black hole, they heat up, giving rise to what is known as an active galactic nucleus (AGN). In large galaxies, AGNs are among the brightest objects in the known universe. But in smaller galaxies, AGNs can be fainter and, consequently, more difficult to distinguish from newborn stars.
"The spectra taken with DESI will help to solve this problem," says Mar Mezcua, IEEC researcher at ICE-CSIC. She adds: "The large extent of the sky covered will produce more information about the nuclei of small galaxies than any previous observation.”
By the end of the project, in 2026, the DESI catalogue is expected to contain more than 35 million galaxies, which will allow a huge variety of cosmology and astrophysics research to be carried out.
Kitt Peak National Observatory, near Tucson, Arizona (USA). The Mayall telescope is visible on the right of the image.
The DESI spectrograph is located inside it (Marilyn Chung/Berkeley Lab).
The DESI collaboration
The DESI instrument is installed on the Nicholas U. Mayall 4-metre telescope at Kitt Peak National Observatory near Tucson (Arizona, United States). It saw its first light in late 2019. The coronavirus pandemic kept the telescope shut down for several months, until December 2020 when DESI returned to look at the sky to test its hardware and software. In May 2021, DESI was ready to start its observations. The project is an international scientific collaboration managed by Berkeley Lab and is funded by the following institutions: U.S. Department of Energy's Office of Science; National Science Foundation of the United States; Division of Astronomical Sciences under contract with the National Optical Astronomy Observatory; Science and Technologies Facilities Council of the United Kingdom; Gordon and Betty Moore Foundation; Heising-Simons Foundation; French Alternative Energies and Atomic Energy Commission (CEA); Consejo Nacional de Ciencia y Tecnología of Mexico; Ministerio de Ciencia, Innovación y Universidades of Spain and the member institutions of DESI. DESI scientists are honoured to be allowed to conduct astronomical research on lolkam Du'a (Kitt Peak, Arizona), a mountain of particular significance to the Tohono O'odham Nation.
The full list of participating institutions and more information about DESI is available here.
Press release made in collaboration with the Communication Offices of: Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Institute of Space Sciences (ICE-CSIC), Institut de Física d'Altes Energies ( IFAE), Institute of Cosmos Sciences of Universitat de Barcelona (ICCUB) and Institute for Theoretical Physics (IFT) UAM-CSIC in representation of DESI collaboration. Adapted version.
Main Image
Nicholas U. Mayall Telescope
Caption: Star trails over the Nicholas U. Mayall 4-meter Telescope on Kitt Peak National Observatory near Tucson, Arizona (USA)
Credits: KPNO/NOIRLab/NSF/AURA/P. Marenfeld
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The Institute of Space Studies of Catalonia (IEEC — Institut d’Estudis Espacials de Catalunya) promotes and coordinates space research and technology development in Catalonia for the benefit of society. IEEC fosters collaborations both locally and worldwide and is an efficient agent of knowledge, innovation and technology transfer. As a result of 25 years of high-quality research, done in collaboration with major international organisations, IEEC ranks among the best international research centers, focusing on areas such as: astrophysics, cosmology, planetary science, and Earth Observation. IEEC’s engineering division develops instrumentation for ground- and space-based projects, and has extensive experience in working with private or public organisations from the aerospace and other innovation sectors.
IEEC is a private non-profit foundation, governed by a Board of Trustees composed of Generalitat de Catalunya and four other institutions that each have a research unit, which together constitute the core of IEEC R&D activity: the Universitat de Barcelona (UB) with the research unit ICCUB — Institute of Cosmos Sciences; the Universitat Autònoma de Barcelona (UAB) with the research unit CERES — Center of Space Studies and Research; the Universitat Politècnica de Catalunya · BarcelonaTech (UPC) with the research unit CTE — Research Group in Space Sciences and Technologies; the Spanish Research Council (CSIC) with the research unit ICE — Institute of Space Sciences. IEEC is a CERCA (Centres de Recerca de Catalunya) center.
Contacts
IEEC Communication Office
Barcelona, Spain
Ana Montaner and Rosa Rodríguez
E-mail: comunicacio@ieec.cat
Lead Researchers at IEEC
Dr. Francisco Castander
Barcelona, Spain
Institute of Space Sciences (ICE-CSIC)
Institute of Space Studies of Catalonia (IEEC)
E-mail: fjc@ieec.cat, fjc@ice.csic.es
Dr. Héctor Gil-Marín
Barcelona, Spain
Institute of Cosmos Sciences (ICCUB)
Institute of Space Studies of Catalonia (IEEC)
E-mail: hectorgil@ieec.cat, hectorgil@icc.ub.edu