Image Details
Open Data from LIGO, Virgo, and KAGRA through the First Part of the Fourth Observing Run
A. G. Abac et al 2026 The Astrophysical Journal 1004 .
Caption: Figure 2.
LIGO Hanford (left) and Livingston (right) frequency-dependent calibration error for a 1 hr time period in O4a starting at 2024 January 15 08:00:00 UTC. The magnitude of the calibration error is shown in the top plots, and the phase of the calibration error (in units of degrees) is shown in the bottom plots. The median systematic error of the calibration is given by the solid line. The 1σ uncertainty on this systematic error is given by the dotted lines. The black dots overlaid on the figure at specific frequencies are direct measurements of the calibration error at a specific frequency during this 1 hr time period. These measurements are made using sinusoidal injections with the photon-calibrator system. These uncertainties are representative of typical LIGO calibration uncertainties throughout O4a.
© 2026. The Author(s). Published by the American Astronomical Society.