- Speaker: Beverly K. Berger, Stanford University LIGO group
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- End Time:
- Location: Zoom
- Type: Lunch Talk
LIGO's goal is the detection of gravitational wave signals. However, every measurement of a potential signal actually measures potential signal plus noise. Thus, one key to detecting signals is to minimize noise. Sometimes an extended period of commissioning can yield overall reduction of the noise level. I will focus, on the other hand, on noise with a characteristic frequency. In 2015, while Advanced LIGO construction was close to finishing, a mysterious source of noise due to ground motion in the Corner Station (where the interferometer's beam splitter and inner test masses live) was found at about 15 Hz. The feature was visible not only in seismographs but also in accelerometers and microphones. Various tests were made by turning things like fans on and off but the source of the feature was never found. It is still with us. Unexpectedly, this same feature shows up in the gravitational wave channel — a very undesirable attribute. I will describe efforts to find both the ultimate source of the noise feature and how the disturbance gets into the gravitational wave channel. This is an ongoing story but the end may be in sight.
