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General Relativity and Quantum Cosmology, gr-qc
Abstract:
The vulnerability of standard detection methods for long-duration
quasi-monochromatic gravitational waves from non-axisymmetric rotating neutron
stars ('continuous waves', CWs) to single-detector instrumental artifacts was
addressed in past work [Keitel, Prix, Papa, Leaci and Siddiqi, Phys. Rev. D 89,
064023 (2014)] by a Bayesian approach. An explicit model of persistent
single-detector disturbances led to a generalized detection statistic with
improved robustness against such artifacts. Since many strong outliers in
semicoherent searches of LIGO data are caused by transient disturbances that
last only a few hours, we extend this approach to cover transient disturbances,
and demonstrate increased robustness in realistic simulated data. Besides
long-duration CWs, neutron stars could also emit transient signals which, for a
limited time, also follow the CW signal model (tCWs). As a pragmatic
alternative to specialized transient searches, we demonstrate how to make
standard semicoherent CW searches more sensitive to transient signals. Focusing
on the time-scale of a single segment in the semicoherent search, Bayesian
model selection yields a generalized detection statistic that does not add
significant computational cost. On simulated data, we find it to increase
sensitivity towards tCWs, without sacrificing sensitivity to classical CW
signals, and still being robust to transient or persistent single-detector
instrumental artifacts.
