OGLE-2013-BLG-1125/MOA-2013-BLG-584: Discovery of a gas giant orbiting an M dwarf

We report the discovery and characterization of a planetary system in the microlensing event OGLE-2013-BLG-1125/MOA-2013-BLG-584. We analyze photometric data from OGLE and MOA surveys, as well as LCO, $\mu$FUN, and Mindstep follow-up telescopes to model the microlensing light curve. We also used data from the Keck II telescope collected in 2018 to obtain additional constraints on the lensing system. We found a Saturn-mass planet of mass $M_{\mathrm{p}}=105\pm 13M_{\oplus }$ orbiting a low-mass host star $M_{\mathrm{L}}=0.139\pm 0.011M_{\odot }$ at $1.00\pm 0.08$ kpc from Earth. This discovery adds to the small sample of giant planets orbiting low-mass stars and provides constraints on planet formation theories.