Research Highlights
NASA's Roman to Peer Into Cosmic 'Lenses' to Better Define Dark Matter
A funky effect Einstein predicted, known as gravitational lensing — when a foreground galaxy magnifies more distant galaxies behind it — will soon become common when NASA’s Nancy Grace Roman Space Telescope begins science operations in 2027 and produces vast surveys of the cosmos.
A particular subset of gravitational lenses, known as strong lenses, is the focus of a new paper published in the Astrophysical Journal coauthored by Simon Birrer, an assistant professor at Stony Brook University. The research team has calculated that over 160,000 gravitational lenses, including hundreds suitable for this study, are expected to pop up in Roman’s vast images. Each Roman image will be 200 times larger than infrared snapshots from NASA’s Hubble Space Telescope, and its upcoming “wealth” of lenses will vastly outpace the hundreds studied by Hubble to date.
Roman will conduct three core surveys, providing expansive views of the universe. This science team’s work is based on a previous version of Roman’s now fully defined High-Latitude Wide-Area Survey. The researchers are working on a follow-up paper that will align with the final survey’s specifications to fully support the research community.
Gravitational lenses are made up of at least two cosmic objects. In some cases, a single foreground galaxy has enough mass to act like a lens, magnifying a galaxy that is almost perfectly behind it. Light from the background galaxy curves around the foreground galaxy along more than one path, appearing in observations as warped arcs and crescents. Of the 160,000 lensed galaxies Roman may identify, the team expects to narrow that down to about 500 that are suitable for studying the structure of dark matter at scales smaller than those galaxies.
“Once Roman’s images are in hand, the researchers will combine them with complementary visible light images from Euclid, Rubin and Hubble to maximize what’s known about these galaxies,” Prof. Birrer said.
Clearest and Most Precise Images of the Universe’s Infancy Revealed
Research by the Atacama Cosmology Telescope (ACT) collaboration has produced new images that are the clearest yet of the universe’s infancy – the earliest cosmic time accessible; the images are of the cosmic microwave background (CMB) radiation that was visible only 380,000 years after the Big Bang.
The international collaboration of scientists includes astrophysicist Neelima Sehgal, PhD, and her group in the Department of Physics and Astronomy in the College of Arts and Sciences at Stony Brook University. The Stony Brook team has played an essential role within the collaboration in analyzing the CMB, the afterglow light from the Big Bang.
The new images measure light that traveled for more than 13 billion years to reach the ACT high in the Chilean Andes and reveal the universe at about 380,000 years old, which the team considers the equivalent of hours-old baby pictures of the cosmos, now in about middle-age.
“We are seeing the first steps towards making the earliest stars and galaxies,” says Suzanne Staggs, Director of ACT and Henry deWolf Smyth Professor of Physics at Princeton University. “And we’re not just seeing light and dark, we’re seeing the polarization of light in high resolution. That is a defining factor distinguishing ACT from Planck and other, earlier telescopes.”
The research team says these results confirm a simple model of the universe and have ruled out most competing alternatives. The new images of the CMB add higher definition to those observed a decade ago by the Planck space-based telescope. Their findings were presented at the American Physical Society Annual Meeting on March 19.
PRL Editor's Choice: Entanglement as a Probe of Hadronization
A recent publication in Physical Review Letters, by scientists at Stony Brook University and Brookhaven National Lab, was selected as an Editor's Choice. The work was done by Research Scientist Jaydeep Datta, Distinguished Professors Abhay Deshpande and Dimitri Kharzeev, Post Doctoral Fellow Charles Joseph Naïm, and Adjunct Associate Professor Zhoudunming Tu.
Previous work had discovered that the proton structure at high energies exhibits maximal entanglement, leading to a simple relation between the proton’s parton distributions and the entropy of hadrons produced in high-energy inelastic interactions, which has been experimentally confirmed.
In this work, the authors extended this approach to the production of jets, where the maximal entanglement predicts a relation between the jet fragmentation function and the entropy of hadrons produced in jet fragmentation. This relation was tested using the ATLAS Collaboration data on jet production at the Large Hadron Collider, and there was good agreement between the prediction based on maximal entanglement within the jet and the data.
This study represents the first use of a quantum entanglement framework in an experimental study of the hadronization process, offering a new perspective on the transition from perturbative to nonperturbative QCD. These results open the door to a more comprehensive understanding of the quantum nature of hadronization.
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