ausblenden:
Schlagwörter:
General Relativity and Quantum Cosmology, gr-qc, Astrophysics, Instrumentation and Methods for Astrophysics, astro-ph.IM
Zusammenfassung:
Tilt-to-length coupling was the limiting noise source in LISA Pathfinder
between 20 and 200 mHz before subtraction in post-processing. To prevent the
adding of sensing noise to the data by the subtraction process, the success of
this strategy depended on a previous direct noise reduction by test mass
alignment. The exact dependency of the level of tilt-to-length coupling on the
set-points of LISA Pathfinder's test masses was not understood until the end of
the mission. Here, we present, for the first time, an analytical tilt-to-length
coupling model that describes the coupling noise changes due to the
realignments. We report on the different mechanisms, namely the lever arm and
piston effect as well as the coupling due to transmissive components, and how
they contribute to the full coupling. Further, we show that a pure geometric
model would not have been sufficient to describe the coupling in LISA
Pathfinder. Therefore, we model also the non-geometric tilt-to-length noise
contributions. For the resulting coupling coefficients of the full model, we
compute the expected error bars based on the known individual error sources.
Also, we validated the analytical model against numerical simulations. A
detailed study and thorough understanding of this noise are the basis for a
successful analysis of the LISA Pathfinder data with respect to tilt-to-length
coupling.
