Incorporating Eccentric Binaries into LISA Global Fits

The future space-based LISA instrument is expected to detect gravitational-waves from tens of thousands of binary systems in the Milky Way. Electromagnetic observations and theoretical population modeling indicate that many of these binaries will have low-to-moderate eccentricities. The current LISA global fit algorithms assume that galactic binaries follow circular orbits, which could lead to parameter biases, larger residuals, and even individual eccentric binaries being reconstructed as a collection of circular binaries. We present a computationally efficient method that starts with circular templates, then smoothly transitions to using the more complicated eccentric model once the eccentricity becomes detectable.