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3rd of April 2024
An artist's impression depicting how nuclear explosions on a neutron star feed the jets ejected from its magnetic polar regions.
Thermonuclear explosions on neutron stars reveal the speed of their jets
by Russell et al.
Relativistic jets are observed from accreting systems throughout the Universe, and have a profound impact on their surroundings. Despite their importance, the jet launching mechanism is not known. For accreting neutron stars, the speed of their compact jets can reveal whether the jets are powered by magnetic fields anchored in the accretion flow or in the star itself. Russell et al. have observed the accreting neutron star 4U 1728-34 with a simultaneous radio and X-ray observing campaign. The radio observations, which probe the jet emission, were taken over a 3-day period with the Australia Telescope Compact Array (ATCA). X-ray monitoring, tracing the accretion flow and detecting the thermonuclear explosions, consisted of a single long observation with the International Gamma-Ray Astrophysics Laboratory (INTEGRAL). With these flares, they measured the speed of a neutron star compact jet to be about one-third of the speed of light, much slower than those from stellar mass black hole systems. This discovery provides a powerful new tool for determining the role that individual system properties have on the jet speed, revealing the dominant jet launching mechanism. The artist's impression above depicts how nuclear explosions on a neutron star feed the jets being ejected from its magnetic polar regions. (Image credit: Danielle Futselaar and Nathalie Degenaar, Anton Pannekoek Institute, University of Amsterdam. License CC BY-SA 3.0)

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