Link to the report:

Important Highlights

• IFO averaged an observing time of around 76%; low observing time (< 60%) on Aug 15 and Aug 16; high observing time (> 90%) on weekend (almost 100% observing time on Aug 19)
• The range fluctuated between 140 - 150 Mpc when in observing mode
  • Exceptions: range momentarily hit 160 Mpc on Aug 17 due to HVAC being turned off (Aug-17); range momentarily hit ~ 155 Mpc on Aug 18
• Fscan line count was consistently below 600 on Aug 14-18; line count was significantly higher (a bit below 650) on Aug 20
• Hveto winners over the week were:
  • (5 days) H1:PEM-EX_VMON_ETMX_ESDPOWER48_DQ
  • (Tied for 3 days each) H1:SUS-ETMX_L3_OPLEV_YAW_OUT_DQ, H1:LSC-POP_A_LF_OUT_DQ, H1:SUS-ETMX_L3_OPLEV_PIT_OUT_DQ
  • Other winners: H1:ASC-CHARD_Y_OUT_DQ (Aug 14), H1:PEM-EX_VMON_ETMX_ESDPOWER18_DQ (Aug 15, Aug 20), H1:ASC-REFL_A_RF45_I_YAW_OUT_DQ (Aug 16), H1:LSC-REFL_A_LF_OUT_DQ (Aug 16), H1:ASC-REFL_A_RF9_I_YAW_OUT_DQ (Aug 17), H1:ASC-Y_TR_A_NSUM_OUT_DQ (Aug 17)
• Significantly fewer high-SNR (at least ≥ 8) glitches for all days this week compared to Aug 13
• Particularly significant excess noise in PEM during observing time:
  • Aug 14, 15, 17, 18, 19, 20: Significant low frequency noise (< 40 Hz) in many ACC and acoustic channels
  • Aug 16, 17, 19, 20: Corner ACCs (only Corner ACCs on Aug 16, but more ACCs on the other days) all seem to have a zig-zag pattern/line around 30-40 Hz
  • Aug 19: Loud burst at 17:00 UTC in YMAN beam tube motion (but not in the XMAN or other corner tube accelerometers); it is also present but not as strong in BSC1 and in the YCRYO floor ACCs
    • Curious short-lived dip in range at same time (17:00 - 17:10 UTC)
• Aug 17: Turning off the HVAC confirmed that the HVAC chiller pumps are the source of the faint 52 Hz line consistently seen this week and in past weeks (Aug-18)
• Strong horizontal lines around 1000 Hz, 500 Hz, and 102 Hz (covers a broader range of frequencies than the other two lines) show up consistently as the IFO enters lock (Aug-14, Aug-18)
  • These lines do not show up for most of Aug 20 as IFO did not lose lock since ~ 4:30 UTC the previous day
• Aug 20: Drastic range dip to slightly below 140 Mpc from 11:30 - 13:00 UTC, especially given how clean the strain noise spectrogram looks and with no clear ground motion correlation
  • In the frequency interval ~ 100 Hz - 170 Hz, the integrated strain at the start of the dip (12:00 UTC) tends to be higher than the integrated strain much earlier on (8:10 UTC)
  • Additional short-lived range dip (also going below 140 Mpc) at 3:30-4:30 UTC seems to correlate with ground motion

Other Highlights

• PEM:
  • Aug 15: Loud burst in BSC10 (Z) that lasted about two hours (16:00 - 18:00 UTC)
  • Aug 17: In EY acoustic noise, loud burst a bit after HVAC was turned off (HVAC turning off between 15:30 - 16:00 UTC shows up as a vertical blue band in most ACCs), as well as dark horizontal line between 20-30 Hz from 10:30 - 16:00 UTC
  • Aug 18: Three vertical blue bands in End BSCs and Acoustic from 16:00 - 17:00 UTC
  • Aug 20: Dark horizontal line between 20-30 Hz in most ACCs + Acoustic
  • Aug 20: Loud burst between 1:00 - 2:00 UTC in the End Floor channel
• Aug 19: More medium-duration templates with new_SNR between 8-9 compared to previous days
• Consistently fewer coincidences in the Hveto channels for each day this week compared to several days the previous week