A (possibly) new spectral line at 36.160 Hz has been visible in Hrec data since the last maintenance, on Tuesday, May 28: see the attached plot. The cyan curve is before the maintenance. The other violet and pink curves refer to the data right after the maintenance and of today respectively.
Could this be an NCal line left on after maintenance #64364 ? I couldn't find any info about both in the logbook or on the list of calibration lines.
BruCo confirmed it. A coherence of 1 is found at 36.16 Hz with NCal_NEN_rotor_freq_err, NCal_NEN_rotor_freq, and similar channels.
On Tuesday the “NEN” NCal was turned, to restored the injected signal at 36.18 Hz (see https://logbook.virgo-gw.eu/virgo/?r=64364). Unfortunately, only the amplitude of the injected signal was adjusted in the NCal_NE_hInj configuration, keeping a wrong phase. As a consequence, this calibration line was not subtracted in h(t) since Tuesday afternoon.
This phase has been fixed today at 12:19 UTC, while the interferometer was unlocked.
The sign of the NEN calibration line at 36.16 Hz was further corrected at 15:32 UTC.
