The Performance of the LIGO Detectors during the Fourth Observing Run

Both the LIGO Hanford and LIGO Livingston detectors have achieved unprecedented sensitivity during the fourth gravitational wave observing run, reaching and even surpassing the 160 Mpc binary neutron star range goal. This improvement in sensitivity is the result of several upgrades to the detectors, including the replacement of core optics, installation of a 300 m filter cavity for the injection of frequency-dependent squeezed light, and the increase in the intracavity power. I will summarize the results of these successful upgrades and report on the significant noise sources that limit these upgraded detectors.