- Updated BruCo scan using the best sensitivity so far (reporting above 100 Mpc), between 1226014475 and 1226014475+400s
https://ldas-jobs.ligo.caltech.edu/~gabriele.vajente/bruco_1226014475/
- Below ~17 Hz, dominated by DHARD pitch and yaw
- INP1 and PRC2 yaw between ~15 Hz and 30 Hz. This coherence is seen also in most of the REFL WFS and most interestingly in some IMC transmission signals, like for example the ISS second loop QPD. I suspect this is an indication of real input beam jitter. Incidentally, sidebands around the 60 Hz line are also coherent with INP1 and PRC2
- There is some interesting coherence with OMC_A_YAW_OUT, but this might be related to the DHARD motion
- at the time, there was a large PCAL line at about 35 Hz, and a lot of coherence with PCAL signals, not only at the line both also broadband. I'm not sure if this happens in the normal state or if there was some injection going on.
- SRCL noise is quite close to the sensitivity between 20 and 150 Hz. PRCL is also close.
- A few peaks are coherent with the PSL periscope accelerometer (about 177 Hz, 223 Hz, 483 Hz, 542 Hz)
Thanks Gabriele, this will be useful. Just want to say for the record that the calibration was wrong during this time, we don't believe our sensitivity was really 100 Mpc.
Too bad, that would have been good. Nevertheless, the coherences are still significant and similar to what reported for earlier lock stretches.
The Pcal lines at the Y-end were turned on at ~1226014752.1 GPS sec (around 277.1 sec after the start of this bruco run) and there was no ramp up of the amplitudes of the lines. The high coherence we see around 30 Hz with PCal singal seems to come from sudden turn on of the lines and also due to spectral leakage. If I calculate the coherence for the first 270 secs or last 120 secs I don't see any such excess coherence.