Research Briefing in 2023

Periodic sub-structure in radio emission from magnetars provides an observational link not only between magnetars and fast radio bursts, but across all classes of radio-emitting rotating neutron stars. The correlation between sub-structure periodicity and neutron-star rotational period can be used to determine an underlying period for fast radio bursts.

The optical properties of the organic hazes that form in water-rich exoplanet atmospheres differ from those that form in nitrogen-rich atmospheres. This difference in optical properties can have an observable effect on spectral observations of exoplanets and could impact the interpretation of current and upcoming JWST observations.

Theories predict that core asphericity must be involved in core-collapse supernova explosions; however, the shape of these explosions has not been directly observed. The distribution of the explosive burning ash has now been revealed using nebular spectroscopy, indicating that a collimated structure is common in many stellar explosions.

Fast radio bursts, arriving at Earth from distant galaxies, usually have durations of a few milliseconds or more. Now, data on a source of repeating fast radio bursts have been revisited, with much higher time resolution than before, and burst signals are seen that last only a few microseconds — showing that the properties of fast radio bursts are more diverse than previously thought.

JWST observations of Jupiter reveal a narrow and intense atmospheric jet at the equator of the planet, close to its tropopause. The jet is manifest in the fast motions of equatorial hazes and is most likely a deep counterpart of the equatorial oscillations observed in Jupiter’s stratosphere.

Through the past 12 billion years of cosmic time, galaxies have been in a near-equilibrium state, with their star-formation rates, stellar masses and chemical abundances tightly connected. But, from JWST observations, it now seems that at earlier times galaxies deviated from this relation, owing to the inflow of pristine gas in the early Universe.

Carbon atoms are one of the most abundant chemical species in the earliest stages of star formation. They had been thought to be immobile on the surface of interstellar ice, but laboratory experiments now show that a significant fraction of carbon atoms can move on the surface and react — changing our view of interstellar organic chemistry.

The Chang’e-6 mission plans to return geological samples from the farside of the Moon by 2025. The spacecraft will land in the four-billion-year-old Apollo crater within the South Pole–Aitken basin: three candidate sites within the crater have been identified and their scientific potential for sample collection has been explored.

The 21-cm absorption lines from neutral hydrogen at cosmic dawn are proposed as a probe to simultaneously study dark matter particle mass and cosmic heating history. By applying a statistical approach to simulated data this probe is shown to distinguish the effects of dark matter from those of cosmic heating.

A dedicated method for analysing moderately saturated measurements from Swift’s Ultraviolet and Optical Telescope is used to perform a time-resolved analysis for the initial white filter exposure of GRB 220101A. This analysis reveals a rapidly evolving ultraviolet and optical flare, distinguished by extremely high luminosity and unexpected temporal behaviour.

Cosmological surveys aim to constrain the ‘gravitational slip’, a key signature of modified gravity — but an as-yet unknown force acting on dark matter could mimic the gravitational slip and invalidate the test. By additionally factoring in a measurement of gravitational redshift, future surveys could have the power to distinguish between these possibilities.

Observations using JWST show water, probably from a subsurface ocean on Saturn’s icy moon, spewing into a large plume that extends far beyond the moon’s surface. This continuous outgassing results in a torus of water along Enceladus’s orbit and is so intense that the plume is the prime source of water across the Saturnian system.

Radial velocity observations of a binary star system have led to the discovery of a gas-giant circumbinary planet, BEBOP-1 c, which is 65 times more massive than Earth, with an orbital period of 215.5 days. The binary system also hosts a smaller, inner transiting planet, TOI-1338 b, making this system a rare multi-planet circumbinary system.

The quantization of spacetime could be revealed indirectly through its imprint on the propagation of particles. An analysis combining data from the IceCube Neutrino Observatory and the Fermi Gamma-ray Space Telescope shows preliminary statistical evidence of such a quantum-spacetime effect.

As pairs of black holes inspiral and merge, they create gravitational waves. These waves hold information about the environment in which the black holes are embedded: using future space-based gravitational-wave detectors, it will be possible to distinguish what kind of environment that is.

A brief but bright flash of optical radiation has been captured only 30 seconds after the onset of a gamma-ray burst. Produced in the interior of the shocked relativistic jet that powered the burst, the optical flash reveals the jet to be narrow and magnetized.

The first maps of the magnetic field in the nebula surrounding the Crab pulsar have been drawn using X-ray polarimetry. They provide insight into the flow of relativistic particles through the nebula and the generation of turbulence.

A laboratory experiment has replicated the braided strands of solar coronal loops and shown that the bursting of individual strands produces X-rays. Measurements of these braided strands and the generated X-rays reveal a multi-scale process that could be responsible for the energetic particles and X-rays that accompany solar flares.

A probabilistic machine learning-based framework for recognizing and predicting microbial landscape patterns at nested spatial scales was developed. The approach substantially increased the probability of detecting biosignatures when tested at a Martian analogue in the high Andes. This search tool has applications for detecting biosignatures on terrestrial or icy planets.

Near-infrared observations of large dark asteroids in the main belt reveal that they have spectral characteristics similar to those of the dwarf planet Ceres. Thermal evolution models suggest that these asteroids accreted at large orbital distances and may have been implanted into the main belt by the dynamic instability of the giant planets.