¶ Scratchy
Particularly at LIGO Hanford, there often occurs a somewhat wide band of mid-frequency glitches that look something like a ripply path through time-frequency space. The glitch path can last for several seconds and be filled with a number of repeating glitches. This was one of the key limitations in searches for binary black hole mergers and the search experts referred to it as "that annoying scratchy noise."
Update: Prior to May 2017 most of the Hanford scratchy glitches seemed to have 12-15 nodes (bright dots) per second though some of them had more. After the May 2017 work on Hanford, in which the "swiss cheese baffle" was damped with rubber corks so that it moves less, most of the scratchy glitches appear with about 25 nodes per second.
Update #2: Further investigation to see what effect the damping of the Swiss Cheese Baffle had on scratchy glitches.link
¶ Examples
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Audio of Scratchy (with associated spectrogram) Make sure to wear good headphones!
