Miriam, Jenne

*SUMMARY*

We check the L1 and L2 FASTIMON channels introduced in Feb 2016 and the L3 LVESDAMON at the times of blip glitches (found on data from Feb 11 and Feb 13). This investigation suggests that the actuation electronics are not the cause of blip glitches, but their origin must be in the interferometer.

*DETAILS*

We investigate 5 different times: 1139199176.774658, 1139240197.712158, 1139246246.086670, 1139400338.701172, 1139412012.846924

The channels we look into are of the kind H1:SUS-(E/I)TM(X/Y)_L(1/2)_FASTIMON_(UL/UR/LL/LR)_OUT_DQ and H1:SUS-ETM(X/Y)_L3_LVESDAMON_(UL/UR/LL/LR)_OUT_DQ.
These channels show the actuation on the mirrors. 

We plot the whitened data from the H1:OMC_DCPD_A_OUT_DQ as well as the whitened data from the channels mentioned above. The vertical lines show the times listed above. In the attachment we show only the channels that showed something significant. When the blip glitches are loud (higher SNR), it can be observed in the plots that the actuation starts pushing on the mirrors only after the DCPD has seen the blip glitch. 
Therefore, the blip glitch must have originated in the interferometer and not in the actuation electronics.