The impact of relativistic corrections on the detectability of dark-matter spikes with gravitational waves
Published:
Today Nick’s first paper has been posted to the arXiv. Congratulations, Nick!
It has been proposed that clumps of dark matter (DM) with extremely high density could grow at the centre of galactic cores under the influence of their supermassive black holes (SMBH). Such a concentration of matter leads to observable features that could hopefully elucidate the nature of DM, and that are currently being looked for in the electromagnetic spectrum.
The gravitational-wave spectrum could be exploited for the same purpose, as pointed out first by Eda et al.. Extreme mass-ratio inspirals (EMRIs) are binaries with an extreme asymmetry in the masses that could be useful for this purpose. In this scenario, a stellar-mass compact object rotates around a SMBH probing the latter’s spacetime and environments with great precision. In the presence of a lot of DM, dynamical friction could slow down the motion of the smaller black hole, thus revealing the presence of an environmental effect.
In our paper, we focus on modelling both the DM spike and dynamical friction force within a fully-relativistic treatment. At least for the circular orbits we consider, relativistic corrections to both have a considerable impact in the detectability of the EMRI within the LISA data stream. Our work is a further step in the quest to probe the galactic cores with GWs.