Improved analytic extreme-mass-ratio inspiral model for scoping out eLISA data analysis

TL;DR

This paper presents an improved analytic EMRI waveform model for eLISA data analysis that maintains phase accuracy over months with minimal computational cost, aiding future gravitational wave research.

Contribution

An augmented Barack-Cutler EMRI waveform model using a frequency map and updated evolution equations for better phase accuracy over extended periods.

Findings

Waveforms stay in phase for months

Maintains low computational cost

Improves accuracy over previous models

Abstract

The space-based gravitational-wave detector eLISA has been selected as the ESA L3 mission, and the mission design will be finalised by the end of this decade. To prepare for mission formulation over the next few years, several outstanding and urgent questions in data analysis will be addressed using mock data challenges, informed by instrument measurements from the LISA Pathfinder satellite launching at the end of 2015. These data challenges will require accurate and computationally affordable waveform models for anticipated sources such as the extreme-mass-ratio inspirals (EMRIs) of stellar-mass compact objects into massive black holes. Previous data challenges have made use of the well-known analytic EMRI waveforms of Barack and Cutler, which are extremely quick to generate but dephase relative to more accurate waveforms within hours, due to their mismatched radial, polar and azimuthal frequencies. In this paper, we describe an augmented Barack-Cutler model that uses a frequency map to the correct Kerr frequencies, along with updated evolution equations and a simple fit to a more accurate model. The augmented waveforms stay in phase for months and may be generated with virtually no additional computational cost.