NEXT ELUSIVES WEBINAR: "Detecting (Axion?) Dark Matter around Black Holes with Gravitational Waves"

The observation of Gravitational Waves (GWs) has opened up a whole new avenue for constraining and detecting particle Dark Matter (DM). One of the most promising systems to study is the Intermediate Mass Ratio Inspiral (IMRI): a stellar-mass compact object such as a neutron star inspiraling towards an intermediate mass black hole, thousands of times more massive than the Sun. Sub-hertz GWs emitted during the inspiral should be detectable by future space-based observatories such as LISA. But the presence of DM in the system can have subtle dynamical effects on the inspiral, altering the waveform and hopefully allowing us to map out the DM distribution. In addition, multimessenger signals can arise when the DM is in the form of QCD axions, in which case the strong magnetic fields around the neutron star allow the conversion of axions to radio photons. Joint observations in GWs and radio would thus provide not only a detection of Dark Matter, but also a striking confirmation of its particle nature.