Single harmonic EMRIs

Extreme-mass-ratio inspirals (EMRIs) are among the most information-rich gravitational-wave sources expected for upcoming space-based detectors like LISA. Most astrophysically relevant EMRIs are expected to have moderate to low eccentricities and nearly equatorial orbits. In this study, we find that much of this LISA detectable parameter space will, in fact, be effectively single mode. We map these regions and show how single-harmonic dominance impacts parameter estimation. We also discuss the wider implications for catalogs and population estimates.