¶ Blip
Blips are short glitches that usually appear in LIGO's gravitational-wave channel with a duration of around 40 ms, typically at frequencies between 30 and 500 Hz at first (though more recently they exhibit a wider range of frequencies) and with a symmetric 'teardrop' shape in time-frequency. Generally they have more normalized energy at the lower frequency end of the teardrop, and their energy is overall modest compared with other glitch classes.
Blips are the single most important class of glitches in Advanced LIGO. They appear in both H1 and L1 and are the most stringent limit on our ability to detect binary black hole merger signals with amplitudes smaller than GW150914. No clear correlation to any auxiliary channel has yet been identified. As a result, there is currently no information available to veto these blips from astrophysical searches, and no good leads for how to fix them in the instruments.
For more information, see http://arxiv.org/abs/1602.03844
¶ Examples
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Audio of Blip (with associated spectrogram) Make sure to wear good headphones!
