Millihertz Gravitational Wave Sources in the Galactic Center

Evidence from stellar orbits and periodic X-ray flares in the galactic center suggest that it harbors a cluster of low-luminosity sub-solar mass objects within a few AU from Sagittarius A* (SgrA*) brought forth via dynamical mechanisms. Any such objects should emit gravitational waves within the Laser Interferometer Space Antenna (LISA) frequency band with large enough amplitudes to be detected by LISA observations. This distinct population of extremely large mass ratio inspirals (X-MRIs; having mass ratio q ≳ 10⁷) includes extended objects that will be subject to tidal excitations and ultimately mass transfer as they orbit closer to the central black hole. Accounting for these effects is necessary to detect and characterize the systems as well as to constrain basic parameters of SgrA*. The search for X-MRIs in the galactic center with waveforms considering matter effects will be incorporated into the Global LISA Analysis Software Suite (GLASS) as a component of the global analysis for LISA gravitational wave sources.