Virgo Logbook

I did a survey of the glitch populations present in the Virgo strain data, starting from the end of January 3, after the injection problems were resolved: #65902. In Figure 1 I report the glitchgram (GPS time vs. frequency at the peak of the glitch trigger, with colorscale and markersize representing the SNR) of the triggers in the analyzed period.

Besides the usual 25-minute glitches, visible as continuous triggers between 40 and 50 Hz, the other glitch families are:

Scatterd Light glitches from bad weather and high microseismic noise, visible as low-frequency trigger clusters on Jan 8-11 (as reported by the operators in entries #65945, #65954, and #65964) Jan 13-14 (#65970).
A family of glitches very loud (SNR > 200) and very fast glitches, with central frequencies in the bucket 60-400 Hz, has appeared since January 8.
At a higher frequency, a third family of glitches, weaker than the previous one, seems to have appeared starting from January 19 (and possibly after the injection system failure: #66002 and #66004).

I tried to investigate the origin of these glitches by repeating the correlation analysis via UPV+VetoPerf reported by Nicolas' in #65906.

At this link the complete result of VetoPerf, which I summarize:

V1:SDB1_OMC1_Peltier_cmd_0 and V1:SDB1_B1_f1_i_DCn_0 seem to act as a veto for a fraction of the glitches with SNR ~1000 in the bucket. However, most glitches in this region did not report any useful channels as vetoes, with the channel list used. More detailed investigations are needed, especially if this very loud family of glitches persists.
The fainter glitch family started yesterday appears similar to, but significantly less severe than, that identified on January 2: #65902. The resulting correlated channels are the same as found by Nicolas in #65906, specifically INJ_* and SIB2_* channels. In the attached gif the glitchgram before and after applying the veto: note that the majority of triggers after January 19 disappear. We will continue to monitor these glitches but they will likely go away once the INJ issues are fully resolved, as happened earlier inJanuary.