There are some jittery peaks that may be doughnut jitter. How much are we going to gain if we squash them?

As a sensor for jittery things I chose IMC WFSA DC YAW. (Not because we believe that it's an angulay jitter, but because the coherence with DARM is high and therefore whatever polluts DARM is likely coming from the same place as the angular jitter measured by IMC WFSA DC YAW.)

Using DTT, I took 100 averages of CAL_DELTAL_EXTERNAL and IMC WFSA DC YAW from the night before (Nov/08 10:00:00 UTC) when there was this fabulously steady BNS inspiral range. As you can see from the first plot, IMC WFS is coherent with CAL_DELTAL_EXTERNAL.

I used the part where coherence is greater than 0.2 and did a dirty subtraction of the WFS signal from CAL_DELTA_EXTERNAL using a transfer function and the spectra measured. 60Hz and harmonics are excluded from the subtraction. The top panel shows both the raw and the post-subtraction spectrum.

The displacement was then divided by 4000 and was plugged into BNS inspiral range code (BNS_range.m) in calibration svn. Note that the range produced this way disagrees with the sensemon by about 10-% (my number overestimates), but it should still be useful for noise subtraction comparison.

In the second attachment, bottom shows the sqrt of the integrand (i.e. to obtain Mpc, you square the plot, add everything together, then sqrt).

The effect of the subtraction is small but not totally negligible, it seems like we'll gain something like 1.5 Mpc (or 1.3Mpc if you believe that the overestimation of the inspiral range is just a scale difference).