Physical Review C

Turbulence deep within the interior of stars bears many qualitative similarities with turbulence in the ocean and atmosphere on Earth. In both contexts, various forms of convective instabilities and shear instabilities govern the transport of heat, momentum (angular momentum) and chemical species. However, an important distinction between stellar fluids and geophysical fluids is the value of the Prandtl number, which is of order unity in oceanic and atmospheric flows, and asymptotically small in stars. As a result, many well-known scaling laws for turbulent transport in geophysical flows must be revisited at low Prandtl number, as reviewed in this paper.

Composition gradients in the interior of Jupiter can affect and even suppress convective motions. In some situations, a composition gradient can trigger the formation of multiple convective layers separated by sharp diffusive interfaces, preventing further mixing. This fluid state, called layered convection, has been proposed to occur in giant planets. However, it is not guaranteed that secondary convective layers can form and survive underneath a turbulent convection zone. Our simulations find that below an evolving convection zone, layer formation is difficult and the fluid always fully mixes. This may have bearing on the survival of composition gradients in Jupiter’s interior.

Fast radio bursts, milliseconds-duration radio bursts predominantly originating from cosmological distances, figure among the unsolved puzzles of contemporary astrophysics. The rapid accumulation of observational data has generated an equally intense theoretical activity toward the understanding of the physical processes at the origin of these events. This review presents a thorough survey of the current knowledge about fast radio bursts, starting with the generic constraints that can be placed on theoretical models based on current observations and plasma physics considerations, then moving to a critical discussion of coherent radiation mechanisms and source models currently debated in the scientific community.

A crucial ingredient in accurate simulations of neutron star-neutron star and neutron star-black hole mergers is the inclusion of neutrino transport and its effects on the physics and astrophysics of these phenomena. The authors implement a neutrino radiative transport scheme in their general relativistic hydrodynamics code, BAM, do more accurately simulate these mergers and map the effects of neutrino transport on the ejecta from neutron star-neutron star mergers.

The new JWST observatory is revealing far more bright galaxies in the early Universe than anyone predicted, and astrophysicists have more than one explanation for the puzzle.

Turbulent power is introduced in to Jupiter’s magnetosphere near the cen- trifugal equator of the plasma disc. Turbulent fluctuations are generated within the plasma fluid. Turbulent energy then travels out of the plasma disc via shear Alfvén waves, dissipating out of the system along the way.

A theoretical proposal presents a framework for microscopic explanation of the entropy of astrophysical black holes.

Scientists have found seven astrophysical tau neutrinos—particles that are notoriously difficult to detect—in an analysis of data from the IceCube Neutrino Observatory in Antarctica.

New solar observations indicate that plasma waves are responsible for the Sun’s outer atmosphere having different abundances of chemical elements than the Sun’s other layers.

Neutrinos can change flavors due to their nonzero masses and mixings as well as their interactions with matter and other neutrinos. In dense astrophysical environments, such as core-collapse supernovae or neutron star mergers, the problem of neutrino flavor evolution becomes very complex. Connections to other domains such as quantum information theory have been uncovered. Understanding the neutrino flavor evolution in dense environments can shed light on the dynamics of massive star explosions and the origin of heavy elements in the Universe and is important for future observations of supernova neutrinos.

A proposed dark matter (DM) search uses the possibility of excess H${}_3^{+}$ in planetary atmospheres due to DM annihilation and uses this idea to place constraints on DM-nucleon cross section using data collected from Cassini’s Jupiter flyby.

Nucleosynthesis during the Big Bang (BBN) can produce the lightest elements, including lithium, but the observed abundance of lithium in old stellar populations is much less than that predicted from BBN. To solve this so-called “lithium puzzle”, it had been postulated that a previously unobserved resonance in ${}^7$Be could deplete lithium through resonant proton capture on ${}^6$Li and thus account for the deficit. The authors performed a detailed study using information from all possible reactions that could be influenced by such a state, utilizing the stringent constraint imposed by the unitarity of the scattering matrix. They conclude that the postulated $3/2^{+}$ state in ${}^7$Be is highly unlikely, but they also suggest that additional radiative capture data are required to solve lingering discrepancies.

Dark matter that interacts with itself could extract significant momentum from a binary supermassive black hole system, causing the black holes to merge.

The largest 3D fully kinetic shearing-box simulations of pair-plasma magnetorotational turbulence which take into account the radiation reaction self-consistently show how particles can be accelerated efficiently to nonthermal energies independently of initial conditions.

The formation of a black hole from light alone is permitted by general relativity, but a new study says quantum physics rules it out.

A way to determine the flavors of ultrahigh-energy cosmic neutrinos observed by future detectors could help scientists understand the origin of these elusive particles.

A correlation between two astronomical observables reveals the influence of visible matter on a universe dominated by dark matter.

An infrared detector is sensitive to a wide range of intensities and could potentially pick up biomarkers from exoplanet atmospheres.

Axions—theorized particles that could account for dark matter—could accumulate around rapidly rotating neutron stars to the point that they become detectable.

Liquid argon detectors have reached an unprecedented level of maturity, owing to a couple of decades of R&D and the operation of large-scale facilities in several particle and astroparticle physics laboratories. After describing the physical and chemical properties of this noble element as an active and target medium for particle detection, the review discusses the opportunities and challenges of liquid argon detectors operated as calorimeters, scintillators, and time projection chambers. A comprehensive panorama of current and future applications is provided, ranging from collider physics to accelerator neutrino beam experiments and underground facilities for the observation of rare events, also including unconventional developments in medical and applied physics.

A “Little Earth Experiment” inside a giant magnet sheds light on so-far-unexplained flow patterns in Earth’s interior.

Two dark matter searches report that their detectors have likely recorded neutrinos coming from the Sun—spotting the “neutrino fog” that could imperil future dark matter searches.

Two dark matter searches report that their detectors have likely recorded neutrinos coming from the Sun—spotting the “neutrino fog” that could imperil future dark matter searches.

Low-frequency radio observations could allow researchers to distinguish among several dark matter models, thanks to dark matter’s influence on the early Universe.

A new analysis of more than a decade’s worth of observations extends the spectrum of cosmic-ray electrons to unprecedented high energies.

Using the techniques of effective field theory and higher-form symmetries, a comprehensive theory of magnetohydrodynamic transport applicable to magnetic diffusion in neutron stars is developed. This analysis not only reproduces known phenomena, such as Ohmic decay, ambipolar diffusion, and Hall drift, but also reveals new terms in the magnetic field evolution equations, which are expected to become important in the presence of strong magnetic fields.

A new analysis challenges the claim that a gamma-ray signal observed from a direction near the Milky Way’s center is produced by a dwarf galaxy.

Scientists have devised a way to use current gravitational-wave detectors to observe permanent deformations of spacetime caused by certain supernovae.

Minerals exposed during an ancient Mediterranean Sea desiccation should reveal damage caused by muons, providing evidence of enhanced cosmic-ray fluxes.

By measuring the melting temperature of iron under high transient pressure, researchers set a limit on the temperature at the boundary between the inner and outer cores.

The paper introduces a novel simulation tool that models radio wave emission from Fast Radio Bursts (FRBs) and accounts for propagation effects due to gravitational lensing, refractive plasma lensing, and interstellar plasma scattering. The tool paves the way to distinguishing intrinsic FRB morphology from nonintrinsic effects.

Gravitational waves open a unique window on the earliest times in cosmology because the dense primordial plasma, impenetrable to light or neutrinos, is transparent to gravitational waves up to the instant of the birth of the Universe. This review discusses the possible signals from the phase transitions, topological defects, and other cosmological sources, as well as a range of strategies for detection of the stochastic gravitational waves produced by the earliest events in the history of the Universe.

Inspired by recent observations of stable cyclone patterns on the North and the South poles of Jupiter, we present observations of monopolar barotropic cyclones in a model experiment for atmospheric polar flows. We show, both experimentally and with idealized quasi-geostrophic simulations, that starting from an initial vortex, there are two evolution regimes depending on vortex strength relative to the local beta-effect across its surface: a Rossby wave emission dominated regime and a strong vortex regime. In the latter regime, the generated cyclone drifts in a northwest direction. We show that the “beta gyre” induced “beta drift” mechanism locally applies in our experimental polar plane.

A five-sigma discrepancy is found in inference of the clustering of matter between the eBOSS 1D Lyman-alpha forest 2019 analysis and the combination of $Planck$ cosmic microwave background, baryon acoustic oscillations, and supernovae data. It is argued that this discrepancy can be resolved either by modifications to the cosmological model or a significant change in the modeling of the intergalactic medium.

The spectrum of cosmic-ray antiprotons has been measured for a full solar cycle, which may allow a better understanding of the sources and transport mechanisms of these high-energy particles.

Extended gamma-ray emissions in the TeV range are typically associated with middle-aged isolated pulsars. The High Altitude Water Cherenkov (HAWC) collaboration finds negative evidence for the hypothesis that millisecond pulsars (MSPs) also source TeV halos. The authors conclude that while MSPs contribute to gamma-ray emissions in the GeV range, isolated pulsars are the likely primary source of TeV halos and comment on the implications for the Galactic Center gamma-ray excess and the Galactic diffuse emission.

Measurements made by the JWST observatory could be used to detect photons emitted by the decay of a hypothetical form of dark matter particle known as the axion.

A realistic 3D supernova simulation shows that neutron stars with masses as low as 1.192 solar masses are possible, resolving the tension between observed low mass neutron stars and theory’s inability to account for them.

The paper applies a novel simulation-based cosmological inference methodology to Dark Energy Survey Year-3-based weak-lensing mass maps. Inclusion of nongaussian statistics strongly improves cosmological constraints, establishing consistency with other work with the same and different datasets.