TJ, Miriam

Miriam found a population of glitches while following up loud background events from PyCBC that seem to be due to ETMY oplev laser glitches.

It seems like ETMY optical lever laser glitches are coupling into h(t) through L2 via the oplev damping loops, similar to how the ETMX oplev laser glitches were found to be coupling into h(t) in alog 31810 from November 2016. These are thought to be laser glitches since they show up strongly in the OPLEV SUM readout.

The attachment shows data from Feb 25th, but I've seen similar behavior from earlier today.

The first page of the attachment shows the BLRMS of the ETMY L3 OPLEV SUM aligned with Omicron triggers in h(t).  
The second page shows the ETMY L3 OPLEV SUM BLRMS aligned with the oplev damping loop error point, which seems to be where the coupling into h(t) is coming from. 
The third page shows the EMTY L3 OPLEV SUM BLRMS aligned with the L2 noisemon, which shows the same coincident glitches.