Scientific Program

Pau-Amaro Seoane (AEI)

Title: The distribution of stars around massive black holes in galactic nuclei - Implications for extreme-mass ratio inspirals of stellar black holes and white dwarfs

Abstract: Mass segregated stellar cusps are the natural configuration for nuclear stellar clusters in steady state with a central massive black hole of mass M <~ few x 10^6 Msun. Detailed N-body and Fokker-Planck studies agree quite well with each other in the description of the bulk properties of the stellar distribution of such systems. For typical initial mass functions, the cluster is in the regime of strong mass segregation and therefore stellar-mass black holes dominate the spatial density in the innermost regions close to the massive black hole. The rates of extreme mass ratio inspirals detectable by LISA will be dominated by the inspiral of stellar-mass black holes. On the other hand, white dwarfs inspirals are particularly interesting, since the GW signal could be accompanied by an electromagnetic flare, so that they are a multimessenger source which could allow us to find out the redshift of the host galaxy. The first question to address is the WD-EMRI rates which, although lower than those of stellar black holes, constitute a significant fraction.