11. Simple coherence spectrogramΒΆ

This example shows the time-variation spectrogram of the estimated coherence between the differential-arm length servo control loop error signal for LIGO-Hanford (H1:LSC-DARM_IN1_DQ) and the motion of an optical periscope used to direct the main laser beam into the Hanford interferometer, around the time of GW170814.

gwpy-plot coherencegram \
    --chan H1:LSC-DARM_IN1_DQ H1:PEM-CS_ACC_PSL_PERISCOPE_X_DQ \
    --start 1186741560 \
    --duration 600 \
    --nds2-server nds.gwosc.org \
    --interactive

(png)

Simple coherence spectrogram