Event rate for extreme mass ratio burst signals in the LISA band

During close encounters with a massive black hole (MBH), stellar mass compact objects and low mass main sequence stars on nearly radial orbits will be traveling at relativistic velocities. During the periastron passage these systems will emit gravitational radiation, and depending on the passage timescale, the radiation may be observable by future spaceborne gravitational wave detectors. However, the encounters will only produce bursts in the detector data streams since the orbital frequencies will be outside the detector's bandwidth. Here we estimate the event rate for extreme mass ratio bursts (EMRBs) that will be observed by the proposed Laser Interferometer Space Antenna (LISA). Our event rate calculation is based on a static, spherical model for a galactic nucleus scaled to the size and mass of the Milky Way bulge. Using this model, we find an event rate of ∼15 yr ^-1 in our galaxy with signal-to-noise ratios greater than five. When scaled out to the Virgo Cluster, our model estimates ∼3 yr ^-1 may be seen from Virgo.