Understanding glitchy noise in interferometric detectors of gravitational waves.

Mejuto-Villa E., Pinto I.M., Principe M., Troiano L. per la Collaborazione KAGRA e la Collaborazione LIGO-Virgo
  Lunedì 26/09   15:00 - 19:00   Edificio Psicologia 2 - Aula 2E   III - Astrofisica
Glitches are idiosyncratic, sporadic transient disturbances affecting interferometric detectors of gravitational waves. Substantial, partially successful, efforts have been made, using instrument and environment monitoring channels, to trace back their origin and eventually suppress them. Glitches exhibit different shapes, energies, and rates. Strong glitches (that are individually detectable against the permanent noise floor) can be flagged, in principle, and the affected data can be discarded. Weak glitches affect data in a subtler way, making the noise floor $heavy-tailed$ and $non-stationary$, thus spoiling the performance of traditional detection/estimation algorithms based on the Gaussian/stationay noise assumption. In this communication we present i) a broad review of the state of the art on glitchy noise; ii) a general parametric model of glitchy noise, based on Middleton impulsive noise theory, that can be easily fitted to model the actual noise of existing gravitational wave detectors; iii) a MIMO (multiple-input/multiple-output) model of an interferometric detector coupled to environmental disturbances, that leads naturally to the possibility of identifying natural waveform dictionaries whereby all glitches can be represented, and suggests the possibility of active strong-glitch subtraction.