Volume 2 Issue 11, November 2018

The field of gamma-ray burst astronomy arguably went through three decades of growing pains before reaching maturity. What development lessons can be learned for the adolescent field of fast radio burst astronomy?

Fast radio bursts were discovered just over a decade ago, and their origin remains a mystery. Despite this disadvantage, astronomers have been using them to investigate the matter through which their bright, impulsive radiation travels.

To date, one repeating and many apparently non-repeating fast radio bursts have been detected. This dichotomy has driven discussions about whether fast radio bursts stem from a single population of sources or two or more different populations. Here we present the arguments for and against.

Physical constraints on the sources of fast radio bursts are few, and therefore viable theoretical models are many. However, no one model can match all the available observational characteristics, meaning that these radio bursts remain one of the most mysterious phenomena in astrophysics.

Multi-wavelength and multi-messenger astronomy will reveal the phenomena that produce fast radio bursts, turning fast radio bursts into sharper tools with which to probe extragalactic plasma.

Contrary to usual assumptions, new astronomical observations suggest that dark matter may be self-interacting. If true this would rule out most popular dark matter particle candidates, including supersymmetric neutralinos, axions and sterile neutrinos, as well as black holes.

The existence of a unique binary object captured in the Jovian Trojan population requires an early migration of the giant planets.

The first fast radio burst (FRB) was discovered in 2007, and in the following decade ~25 more were detected. Now the field stands on the brink of an explosion of detections, largely driven by the availability of new radio facilities. One of the founders of the field, Duncan Lorimer, reviews the early years of FRB science.

The second decade of fast radio burst (FRB) astronomy has started at pace, with detections of tens of new FRBs from newly operational facilities such as ASKAP and CHIME. Evan Keane looks forward to the upcoming years and the discoveries they will bring.

Cosmochemical evidence is used to constrain models of Jupiter formation, which unfolds in three distinct phases: a rapid pebble accretion during the first Myr, followed by a slower growth controlled by larger planetesimals, ending in a runaway gas accretion stage.

The Patroclus–Menoetius Jupiter Trojan binary could survive its travel from the Kuiper belt to Jupiter’s orbit only if the giant planets’ migrations happened within ~100 Myr after the birth of the Solar System and not after ~700 Myr, as suggested instead by the Late Heavy Bombardment.

Precise measurements of the motion of Beta Pictoris obtained by Hipparcos between 1990 and 1993 and by Gaia ~24 years later allowed the mass of its planet Beta Pictoris b to be measured. The result of 11 ± 2 Jupiter masses supports ‘hot start’ formation models.

Probing the pre-explosion environments of hydrogen-poor superluminous supernovae is important for understanding how they exploded. Here, Lunnan et al. infer the presence of a fast-moving circumstellar shell around iPTF16eh through the detection of a resonance-line light echo, which indicates the massive progenitor experienced pulsational pair instability shell ejections.

The mechanisms that sustain turbulence in a molecular cloud are not well understood. Using magnetohydrodynamic simulations, the effects of stellar winds on a cloud are studied, finding that energy can be efficiently transferred in magnetic waves generated by this stellar ‘feedback’.

Using commissioning data from the Australian Square Kilometre Array Pathfinder (ASKAP), parts of the Small Magellanic Cloud (SMC) have been mapped with ten times the resolution of before. Cold H i outflows are found to extend some 2 kpc from the SMC bar, containing up to 3% of the galaxy’s atomic mass. These will probably be stripped by interactions with neighbouring galaxies.

A data-driven study of the too-big-to-fail problem of Milky Way dwarf spheroidals within the self-interacting dark matter paradigm finds a good description of their stellar kinematics and compatibility with the concentration–mass relation of pure cold dark matter simulations.

A 3D magnetohydrodynamic model forecasted the state of the solar corona during the eclipse that occurred on 21 August 2017, using observations taken ten days before the eclipse as boundary conditions. The agreement between the predicted images and those observed during the eclipse is very good.

The Australian Square Kilometre Array Pathfinder will be a key tool in future searches for fast radio bursts and other transient phenomena, and is already reaping rewards, explains Principal Engineer Keith Bannister.