  The Advanced LIGO detectors have recently completed their second observation
run successfully. The run lasted for approximately 10 months and lead to
multiple new discoveries. The sensitivity to gravitational waves was partially
limited by correlated noise. Here, we utilize auxiliary sensors that witness
these correlated noise sources, and use them for noise subtraction in the time
domain data. This noise and line removal is particularly significant for the
LIGO Hanford Observatory, where the improvement in sensitivity is greater than
20%. Consequently, we were also able to improve the astrophysical estimation
for the location, masses, spins and orbital parameters of the gravitational
wave progenitors.
