Topic: compact objects

Ulrich Sperhake and Seppe Staelens explain hypothetical boson stars and how researchers use mathematical modelling to investigate them. The discussion connects these unusual compact objects to black holes, gravity and gravitational-wave observations.

Ania Liu examines gravitational-wave lensing as a probe of compact objects, dark matter and cosmic large-scale structure. Propagation over cosmological distances can distort signals, but identifying lensing in observations requires disentangling those distortions from uncertain waveform models and other astrophysical effects. The talk describes this phenomenology and the ambiguities it creates for interpretation, then presents recent methods and results from lensing searches using LIGO–Virgo–KAGRA data.