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Sub-torque-balance Upper Limits on Continuous Gravitational Waves from Scorpius X-1
A. G. Abac et al 2026 The Astrophysical Journal Letters 1010 .
Caption: Figure 6.
The marginalized upper limits from Figure 5, expressed in terms of the quantity known as sensitivity depth (B. Behnke et al. 2015; C. Dreissigacker et al. 2018) ﹩D=\sqrt{S(f)}/{h}_{0}^{\,{\rm{ul}}\,}﹩, which scales out the effect of detector sensitivity by using the averaged noise power spectral density S(f) for the observing run in question. Note that the (resampling) O2 search of Y. Zhang et al. (2021) and the (demod) O3 search of B. P. Abbott et al. (2022a) have similar sensitivity depths of around 50–60 Hz−1/2, with the longer coherence time of the resampling analysis being offset by the longer duration of O3. The variable choice of Tmax in the O3 analysis, designed to trade off computing cost versus scientific return, results in a deeper search at low frequencies and shallower at high frequencies. The present O4a resampling analysis achieves a sensitivity depth of around 70–75 Hz−1/2.
© 2026. The Author(s). Published by the American Astronomical Society.