Shifter: Sumeet Kulkarni

Fellow/Mentor: Greg Vaughn-Ogin

• The overall duty cycle was 73.6% Observing at a BNS range of ~110 MPc.
• There was a large amount of low-frequency scattering persistent around 10 Hz. band throughout. The noise levels dipped on Wednesday, April 4 from 10:00 UTC up until 3:00 UTC on Thursday, April 5 (Seen before during ER13 (alog47931). These glitches were picked out by HVETO from the Output Mode Cleaner ASC POS_Y and POS_X channels.
• Loud glitches appeared at a significant rate (compared to O2) throughout and were picked out prominently by the witness channel H1:LSC-POP_A_LF_OUT_DQ in HVETO.
• High winds and microseism lead to increased scattering at around 30 Hz. and loss of lock on April 6 and 7. alog48288
• Three Earthquakes were logged: 2 lead to lock loss (on April 5 and 6) and one did not affect the re-locking stage (April 7). alog48262 alog48288 alog48302

Complete details can be found at https://wiki.ligo.org/DetChar/DataQuality/DQShiftLHO20190401