The merger of a neutron star with a stellar mass black hole is one of the main sources of gravitational waves detectable by current ground-based observatories (LIGO, Virgo, KAGRA). The first two detections of these mergers were in fact just performed in 2020, with more events expected in future observational runs of LIGO/Virgo/KAGRA. If the neutron star is tidally disrupted by its black hole companion, mass ejection during and after merger also powers bright electromagnetic transients, including gamma-ray bursts and kilonovae. The ejected matter then undergoes rapid neutron capture nucleosynthesis (r-process), leading to the production of many heavy elements (gold, platinum, uranium,…). Both gravitational wave and electromagnetic signals carry information about the properties of the dense matter at the core of neutron stars, an important unknown in nuclear physics today.
Host: Salvatore Vitale