Transient noise created by scattered light in the LIGO Livingston Observatory

The ground based gravitational wave detectors like LIGO are very sensitive to different types of noise arising from the instrumental artifact or some environmental source. It is extremely important to characterize these sources of noise and mitigate them to increase the sensitivity of the detector to astrophysical gravitational wave signals. One of such noises is produced by the laser light being scattered off the mirrors. This noise appears as transient noise or glitches in the data and affects the sensitivity of the detector in the 10-60 Hz frequency band. Any reflective surface inside the detector which is not well isolated from the ground motion can be a potential source of scattered light noise. From the beginning of the fourth observation run, a lot of glitches caused by scattered light have been appearing in the LIGO Livingston detector. The rate of these glitches directly correlates with the increased microseismic ground motion. These glitches were present in the third observation run but they are different in the fourth observation run. We present investigations on the characteristics of these glitches that allow us to identify their sources and coupling mechanism to the gravitational wave data stream.