The first plot attached is a 3mHz bandwidth spectrum of the calibrated DARM signal from last night's 4-hour lock.

Note the dips in the spectrum around the bounce and roll modes of the quad suspensions (9.78Hz and 13.9Hz, respectively).  Evan and I tracked these down to bandstops in the ETMX L1 LOCK_L filter bank that are not included in the calibration (because we don't have a hi-resolution loop gain measurement of DARM at those frequencies).

The second plot attached is a zoom of the region around the violin modes.  In preparation for some aggressive violin mode damping, I've populated the test mass L2_DAMP filter banks with bandpasses at frequencies for various collections of lines.  At the next late-night lock opportunity we'll apply the violin mode damping method that's described here (which has already been successfully applied for the 508.008Hz mode on ETMY) and see what we can do.

The initial assignment of modes --> optics follows the frequencies that were collected by Nutsinee here, but for the forests around 501-2Hz and 504-7Hz it's very rough guesswork.  Here is a list of the mode frequencies (measured from last night's data) and a rough assignment to optics:

Also on the to-do list is to move the OMC alignment dither lines up above 1.5kHz and optimize the dither amplitude based on the OMC DCPD RIN noise floor in that band.