A look at env coherences (up to 100Hz) of the 15mins dark fringe lock: see the bruco hres table

Attached Fig 1 is a sort of coherence projection of ENV channels, different colors corresponds to different sensors type: seismic, magnetic, acoustic, etc...

Most interesting ones:

• 11.5Hz and 12.5Hz are intense narrow lines, they are coherent with similar lines in CEB magnetometer (might they be calibration lines?)
• 17.5 Hz is a quite intense line, it has some coherence with a (...no to similar...) similar structure in TCS WI bench seismometer and CEB magnetometer: Fig.2
• 31 Hz is a quite intense acoustic line, it is coherent with mics in the CEB hall (no laser lab) and accelerometers: see Figure 3
• 1Hz comb shows up between 35Hz and 50Hz, it is coherent with CEB mags and power lines (we suspect the CT heaters... VAC people is working to mitigate this...)
• big calibration lines at 54.1Hz, 67.1, 87.1 Hz have noticeable 2.4Hz sidebands ...
• 75Hz, 83.0Hz, 87.9Hz, 91.9Hz lines are coherent with similar structures in CEB hall seismic sensors.