Using a Gas Jet to Bring Cosmic X-Ray Bursts into the Laboratory

Using a combination of experimental facilities, researchers directly measured a key reaction that takes place in the explosions on the surfaces of neutron stars. This is the first-ever measurement of this reaction. Contrary to expectation, the experimental data agreed with predictions from a common theoretical model used to calculate reaction rates.

STAR Physicists Track Sequential ‘Melting’ of Upsilons

Recent data from the Relativistic Heavy Ion Collider show how three distinct variations of particles called upsilons “melt,” or dissociate, in the hot particle soup that existed in the very early universe. The results from the STAR experiment support the theory that this hot matter is a soup of “free” quarks and gluons. Measuring how different upsilons dissociate helps scientists learn about the quark-gluon plasma.

PREX, CREX, and Nuclear Models: The Plot Thickens

Recent experiments involving a tiny left-right asymmetry in electron scattering off lead-208 and calcium-48 indicate a disagreement between the experiments’ results and the predictions of global nuclear models. This result indicates a need to investigate limitations of current nuclear models or other sources of uncertainty. This has repercussions for scientists studying topics from neutron skins to nuclear symmetry energy to neutron star physics.

Building Bridges and Ladders in Astrophysics: Theory and Experiment Inform the Equation of State

Researchers are combining experimental, theoretical, and observational data on neutron stars to constrain the equation of state (EOS) and to glean the composition of their interiors. Different techniques probe the EOS at different densities, thereby creating a “density ladder” that aims to connect the various rungs. The findings indicate a possible phase transition in the interior of neutron stars.

How Large Are Neutron Stars?

An interdisciplinary research team has identified new, narrower limits on the radii of neutron stars—close to 11 kilometers. The novel approach combined two sources of information: the first gravitational-wave and electromagnetic observations of a binary neutron-star collision, and modern nuclear-theory calculations of uncertainty. The results suggest that neutron-star black-hole collisions can swallow neutron stars whole.

Probing the “Equation of State” of Neutron Matter—The Stuff that Neutron Stars Are Made Of

To predict the properties of matter in a neutron star, physicists consider a theoretical model that consists of an infinite system of pure neutrons that interact by the strong nuclear force. This allows them to calculate the neutron matter equation of state and thus how much weight the star can support before gravity crushes it into a black hole.

NRAO’s Baseline Episode 4: Measuring the Expanding Universe

How fast is the universe expanding? We don’t know for sure.Astronomers study cosmic expansion by measuring the Hubble constant. They have measured this constant in several different ways, but some of their results don’t agree with each other. This disagreement, or tension, in the Hubble constant is a growing controversy in astronomy.

UAH has significant role in LEAP, a mission selected for NASA flight review

In collaboration with Marshall Space Flight Center (MSFC), the Center for Space Plasma and Aeronomic Research (CSPAR) at The University of Alabama in Huntsville (UAH) has a significant role in LEAP – the LargE Area burst Polarimeter – a mission that is one of four proposals approved by NASA for further review.