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Free keywords:
General Relativity and Quantum Cosmology, gr-qc, Astrophysics, Instrumentation and Methods for Astrophysics, astro-ph.IM, Astrophysics, Solar and Stellar Astrophysics, astro-ph.SR
Abstract:
Most continuous gravitational-wave searches use Taylor expansions in the
phase to model the spindown of neutron stars. Studies of pulsars demonstrate
that their electromagnetic (EM) emissions suffer from timing noise, small
deviations in the phase from Taylor expansion models. How the mechanism
producing EM emission is related to any continuous gravitational-wave (CW)
emission is unknown; if they either interact or are locked in phase then the CW
will also experience timing noise. Any disparity between the signal and the
search template used in matched filtering methods will result in a loss of
signal-to-noise ratio (SNR), referred to as 'mismatch'. In this work we assume
the CW suffers a similar level of timing noise to its EM counterpart. We inject
and recover fake CW signals, which include timing noise generated from
observational data on the Crab pulsar. Measuring the mismatch over durations of
order ~ 10 months, the effect is for the most part found to be small. This
suggests recent so-called 'narrow-band' searches which placed upper limits on
the signals from the Crab and Vela pulsars will not be significantly affected.
At a fixed observation time, we find the mismatch depends upon the observation
epoch. Considering the averaged mismatch as a function of observation time, we
find that it increases as a power law with time, and so may become relevant in
long baseline searches.
