Two Stony Brook University Department of Physics and Astronomy faculty in the College of Arts and Sciences recently received the Department of Energy (DOE) Early Career Award for their individual research projects related to the discovery of dark energy and dark matter.
Assistant Professor Anja von der Linden was awarded for her project, “Towards Precision Cluster Cosmology with Large Synoptic Survey Telescope (LSST)”; Assistant Professor Marilena Loverde, also appointed in the Yang Institute for Theoretical Physics, was awarded for “Discovering Dark Energy, Dark Matter, and Neutrino Properties with Cosmic Structure.” Each will receive $750,000 over five years to develop their research.
“This is a wonderful distinction for both Professors von der Linden and Loverde, whose research programs will greatly help us further understand the origin and evolution of the Universe,” said Stony Brook University President Samuel L. Stanley Jr. “The Department of Physics is fortunate to have these scientists among its faculty, both of whom are well deserved of the prestigious Department of Energy Early Career Award.”
The Early Career Research Program, now in its eighth year, supports the development of individual research programs of outstanding scientists during the crucial early career years and simulates research careers in the disciplines supported by the DOE Office of Science.
“Marilena Loverde and Anja von der Linden’s work exemplifies the world-class research being conducted by our outstanding faculty,” says Michael A. Bernstein, Provost and Senior Vice President for Academic Affairs at Stony Brook University. “We are tremendously pleased about this much-deserved recognition for two of our rising stars.”
Both von der Linden’s and Loverde’s research programs address the mystery of the composition of the Universe: less than five percent is in a form of matter familiar to us – planets, stars, gas, photons, and neutrinos. The vast majority of the Universe is in the form of dark matter (about 25 percent) and dark energy (about 70 percent). While dark matter is a form of matter that does not interact with us apart from gravity, dark energy is even more mysterious — it describes the puzzling fact that the expansion of the Universe is accelerating, rather than slowing down due to gravity. Prof. von der Linden compares it to ”throwing a ball up in the air, and, after initially slowing down, seeing it accelerate upwards.”
The Department of Energy is involved in several large cosmic surveys, which will provide precision maps of the Universe on the largest scales. These maps themselves are snapshots of the Universe over the past several billion years of cosmic history. From them, we can study the origin and evolution of structure in our Universe and learn about dark energy, dark matter, and the elusive neutrino. Professor Loverde’s research focuses on the theoretical framework for modeling and interpreting cosmic structure; Professor von der Linden’s research focuses on measurements of the distribution of the largest objects in the Universe, clusters of galaxies, as a way of quantifying cosmic structure.
“My research will develop the theory of structure formation in the presence of cosmic neutrinos and other novel types of matter,” Professor Loverde said. “Despite being the second most abundant particle in the known universe, we don’t know how much the neutrino weighs. This is something we hope to learn from cosmic surveys, but we need a more complete theory of cosmic structure formation. My primary goal is to make sure that our models are sufficiently accurate to detect the neutrino mass, but this work will also generate new tools to study dark matter, dynamical dark energy, and structure formation in the Universe.”
“Solving the puzzle of dark energy requires precision measurements of the expansion history and evolution of structure of the Universe,” Professor von der Linden said. “Clusters of galaxies provide particularly powerful measurements of the Universe, as the number of clusters as a function of mass and its evolution with time is very sensitive to the details of the inner workings of the Universe, including the properties of dark energy, dark matter, and the masses of neutrinos. The challenge for cluster cosmology lies in accurately measuring the masses of clusters, and the most promising technique to determine the absolute mass calibration of clusters is through weak gravitational lensing.”
Loverde’s research aims to develop theoretical templates for several large DOE projects, including the Large Synoptic Survey Telescope (LSST), the Dark Energy Spectroscopic Instrument (DESI), and a Stage IV Cosmic Microwave Background (CMB-S4) survey. von der Linden’s project aims to provide the precision measurements necessary to compare to theoretical predictions; in this case, cluster mass estimates based on the weak-lensing capabilities of LSST. The 8.4-meter LSST is currently being constructed in Chile, and will feature the largest digital camera ever built, with over 3200 megapixels (the sensors for the camera are being developed at nearby Brookhaven National Lab).
“Professors von der Linden and Loverde are pursuing one of the central questions in cosmology: 95% of the matter in the Universe is unaccounted for,” says Sacha Kopp, Dean of the College of Arts and Sciences. “Their studies bring us closer to understanding the make-up and origin of the Universe.”
Starting in 2023, LSST will image the entire night sky once every three nights, and continue to do so for 10 years.
This will create the deepest image of the Universe over half of the entire sky. LSST will sensitively measure the shapes and distances of billions of galaxies. “Weak lensing” refers to the statistical analysis of these in order to infer the distortion of space-time due to the matter distribution of the Universe. The purpose of von der Linden’s project is to develop and test techniques necessary to utilize LSST weak-lensing data for cluster cosmology, and apply them to targeted pre-cursor as well as LSST data.
“This award is fantastic news for our research group, and I am grateful to the DOE for supporting our work,” von der Linden says. “LSST will be a tremendously exciting project, and I look forward to Stony Brook taking part in it. The results of our project will enable cluster surveys to harness their tremendous statistical potential and be a leading probe of cosmology in the next decade.”
“I am absolutely thrilled to receive this award,” Loverde says. “I’m extremely grateful to the Department of Energy for this support. This is a huge boost for the cosmology group here at Stony Brook University, and I’m excited about the work ahead.”
Prior to joining the College of Arts and Sciences Department of Physics and Astronomy in 2015, Professor von der Linden was a Tycho Brahe fellow at the DARK Cosmology Centre in Copenhagen and the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), Stanford University. She received her PhD in astrophysics from the Max-Planck-Institute for Astrophysics, Garching, Germany, and the Ludwig-Maximilians-Universität, München, Germany.
Professor Loverde joined Stony Brook College of Arts and Sciences in 2015, holding a joint appointment in the C.N. Yang Institute for Theoretical Physics (YITP) and the Department of Physics and Astronomy. She received a BA in Mathematics and Physics from the University of California, Berkeley, in 2003, and a PhD in Physics from Columbia University in 2009. Prior to joining Stony Brook University she was a postdoctoral fellow at the University of Chicago and at the Institute for Advanced Study.
— Rachel Rodriguez