Volume 1 Issue 12, December 2017

Pulsar timing arrays may well be the next type of experiment to detect gravitational waves. Sensitive to lower frequencies than LIGO–Virgo, they will detect the stochastic background of massive binary black hole mergers.

Pulsars — fast-spinning neutron stars — are precision clocks provided by nature. Finding pulsars in the Galactic Centre orbiting Sagittarius A*, the closest supermassive black hole to the Earth, will offer unprecedented opportunities to test general relativity and its alternatives.

More than 20 GW of power are necessary to balance the heat emitted by Enceladus and avoid the freezing of its internal ocean. A very porous core undergoing tidal heating can generate the required power to maintain a liquid ocean and drive hydrothermal activity.

The detection of bright, rapid optical pulsations from pulsar PSR J1023+0038 have provided a surprise for researchers working on neutron stars. This discovery poses more questions than it answers and will spur on future work and instrumentation.

Orbiting supermassive black holes in the centres of nearby galaxies contribute to a gravitational-wave background over the whole sky. Networks of millisecond pulsars are sensitive to this signal. Creating maps of this background using information from known galaxies can help us to project when (and how) we may observe it.

Black holes absorb everything and emit nothing, yet relativistic jets of plasma are observed to emanate from systems hosting accreting black holes. We now know exactly how far from the black hole these processes take place.

IAU Symposium 337 was held at Jodrell Bank Observatory in September 2017 to celebrate the past fifty years of pulsar astrophysics and to look forward to the next fifty.

On the 50th anniversary of the discovery of pulsars Jocelyn Bell Burnell reflects on their detection, our current understanding of these stars and the new era of discovery ushered in by next-generation radio observatories.

The Lovell Telescope at the Jodrell Bank Observatory has played a fundamental role in pulsar astronomy from the discovery of pulsars until the present day. This Perspective reviews the telescope’s accomplished history in astronomy and the early space race.

Tidal forcing within a very porous (unconsolidated) core can generate enough energy to drive all the observed global features of Enceladus. This activity can be sustained up to several billion years.

The atmosphere of evolved star W Hya has been resolved with ALMA and shown to be shock heated. These observations provide important empirical constraints for the understanding of circumstellar structure, convection, chemistry and pulsation.

Optical pulsations from a millisecond pulsar that had transitioned from a rotationally powered regime to an accretion disk state have been detected. The optical emission is likely to be due to electron synchrotron emission in a rotation-powered magnetosphere.

A delay between rapid optical and X-ray flux variations from an accreting black-hole binary is reported together with a brightening radio jet, indicating a characteristic elevation of the radiative jet base of 0.1 light-seconds above the black hole.

The discovery of the most energetic transient event to date is reported. Its spectroscopic properties and temporal evolution imply it is powered by shock interaction between expanding material and large quantities of surrounding dense matter.

Saturn’s proton radiation belts are quite an isolated system and can be used as a laboratory for endogenous impacts on planetary radiation belts. Their evolution over a solar cycle shows variations associated with changes in magnetospheric radial diffusion.

The inner four planets of the TRAPPIST-1 system experienced induction heating due to magnetic interaction with their host star. This led them to experience increased volcanic activity, outgassing and potentially a subsurface magma ocean.

We calculate the continuous nanohertz gravitational-wave emission from individual supermassive black hole binaries and the gravitational-wave background they generate, which will be observable with pulsar timing arrays.

The Neutron star Interior Composition Explorer (NICER) is looking for neutron stars and pulsars from its perch on the International Space Station. Keith Gendreau and Zaven Arzoumanian provide an overview of its capabilities.

Forty years ago, the two Voyager spacecraft left Earth to begin one of the most rewarding voyages of human discovery ever to have been undertaken. Project Scientist Ed Stone recounts his treasured moments from the mission.