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Abstract

We study the properties of the gravitational wave (GW) emission between
$10^{-5}$ Hz and $50$ Hz (which we refer to as low-frequency emission) from
core-collapse supernovae, in the context of studying such signals in laser
interferometric data as well as performing multi-messenger astronomy. We pay
particular attention to the GW linear memory, which is when the signal
amplitude does not return to zero after the GW burst. Based on the long term
simulation of a core-collapse supernova of a solar-metallicity star with a
zero-age main sequence mass of 15 solar masses, we discuss the spectral
properties, the memory's dependence on observer position and the polarization
of low-frequency GWs from slowly non (or slowly) rotating core-collapse
supernovae. We make recommendations on the angular spacing of the orientations
needed to properly produce results that are averaged over multiple observer
locations by investigating the angular dependence of the GW emission. We
propose semi-analytical models that quantify the relationship between the bulk
motion of the supernova shock-wave and the GW memory amplitude. We discuss how
to extend neutrino generated GW signals from numerical simulations that were
terminated before the neutrino emission has subsided. We discuss how the
premature halt of simulations and the non-zero amplitude of the GW memory can
induce artefacts during the data analysis process. Lastly, we also investigate
potential solutions and issues in the use of taperings for both ground and
space-based interferometers.