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Abstract

The LIGO-Virgo-Kagra (LVK) collaboration has detected gravitational waves
from 90 Compact Binary Coalescences. In addition to fortifying the linearized
theory of General Relativity (GR), the statistical ensemble of detections also
provides prospects of detecting nonlinear effects predicted by GR, one such
prediction being the nonlinear gravitational memory effect. For detected
stellar and intermediate mass compact binaries, the induced strain from the
memory effect is one or two orders below the detector noise background.
Additionally, since most of the energy is radiated at merger the strain induced
by the memory effect resembles a step function at the merger time. These facts
motivate the idea of coherently stacking up data streams from recorded GW
events at these merger times so that the cumulative memory strain is detected
with a sufficient SNR. GW detectors essentially record the integrated strain
response at time scales of the round trip light travel time, making future
space-based long arm interferometers like LISA ideal for detecting the memory
effect at low frequencies. In this paper, we propose a method that uses the
event catalog of ground-based detectors and searches for corresponding memory
strains in the LISA data stream. Given LVK's O3 science run catalog, we use
scaling arguments and assumptions on the source population models to estimate
the run time required for LISA to accumulate a memory SNR of 5, using triggers
from current and future ground-based detectors. Finally, we extend these
calculations for using beyond LISA missions like ALIA, AMIGO, and Folkner to
detect the gravitational memory effect. The results for LISA indicate a
possible detection of the memory effect within the 10 year LISA mission
lifetime and the corresponding results for beyond LISA missions are even more
promising.