Related to the recent bad weather conditions, and the consequent high level of microseismic noise, we've had other episodes of Scattered Light glitches. I report here the study of these periods, mainly to keep track of them and to be searchable in the logbook for future or more in-depth analysis.
Figure 1: Glitchgram of the strain channel between September 9 and 12 at 6:00 UTC, with the time series of the three axes of the Central Building seismometer reported below. At the extremes of this range, a high density of triggers (markers in the scatterplot) can be observed, coincident with the high amplitude of the rms signal of the seismometers.
Figure 2: Q-scan of the last hour before the unlock on September 12. Several excesses of noise are visible. A few of them are particularly loud, such as those in Figure 3, with SNR > 1000; these could be analyzed with dedicated omicron scans (work in progress...). The vast majority of the glitches have much fainter SNR. Most of them resemble arcs in the spectrograms, therefore Scattered Light glitches. However, between 5:15:40 and 5:15:45 UTC, a dense band of glitches is noted (Figure 4), in which the characteristic shape of Scattered Light glitches is no longer identifiable. Investigations on this band are ongoing (maybe with a coherent analysis of this short segment of data...).
Figure 5: We performed the usual correlation analysis of Scattered Light glitches, already described in previous entries (#63761, #64022 , ...), using all the raw channels with units of position, speed, and acceleration. The most correlated channels are all the position ones (from which the speed information was obtained). In the attached file all those with correlation larger than 0.3. The figure shows the most correlated channel, in a 10-second interval, where the overlap of the reconstructed scatterer velocity and the Sattered Light glitches can be clearly seen. The result is similar to what was already observed in April and discussed these entries: #64022 and #64026.
