Nice night lock, here is the report from BruCo:
https://ldas-jobs.ligo.caltech.edu/~gabriele.vajente/bruco_1121900417/
An excerpt. As usual, the selection of channels might not be the most representative of the real noise couplings, but should give some good hints.
-
Around 10 Hz there is coherence with ITMY_M0_NOISEMON_LF_DQ. Is this part of the control signal? Should I remove it from the channel list? (fig. 1)
-
SRCL is the winner below 20-30 Hz (fig. 2). In the same region there is coherence with some SR3 signals, in particular M2_OLDAMP. Is this optical lever damping noise? (fig. 3)
-
MICH is not far below SRCL, up to 40-50 Hz (fig. 4). PRCL shows some coherence too, but not very high levels.
-
There is coherence with some OMC ASC signals (fig. 5)
-
It's not very close to the sensitivity, but we also see some coherence with OM1/OM2 signals (fig. 6). The same pattern is visible in ASC_B_PIT and YAW. This is the dominant coherence in the 50-100 Hz region
-
At 74-74.5 Hz there is coherence with PEM-EY_MIC_VEA_PLUSY and with a magnetometer at EY
_VEA_PLUSY
_DQ
-
At 111.5 Hz and 128 Hz there is coherence with PEM-EY_MAG_EBAY_SEIRACK_Z_DQ
-
Coherence with IMC angular signals (and ISS signals) has a pattern slightly different from usual: there are few peaks between 100 and 700 Hz (fig. 7). The same coherence pattern is visible with the periscope accelerometer (fig. 8) and POP_A_RF9_I_ERR. This is the dominant coherence in the 100-350 Hz region and around 600-630 Hz
-
There is still broadband coherence with AS signals, for example ASC-AS_A_DC_SUM_OUT_DQ (fig. 9). This seems to be the dominant coherence above 400 Hz.