We report the discovery of a giant planet in the OGLE-2017-BLG-1522 microlensing event .
The planetary perturbations were clearly identified by high-cadence survey experiments despite the relatively short event timescale of t _ { E } \sim 7.5 days .
The Einstein radius is unusually small , \theta _ { E } = 0.065 mas , implying that the lens system either has very low mass or lies much closer to the microlensed source than the Sun , or both .
A Bayesian analysis yields component masses ( M _ { host } ,M _ { planet } ) = ( 46 _ { -25 } ^ { +79 } , 0.75 _ { -0.40 } ^ { +1.26 } ) ~ { } M _ { J } and source-lens distance D _ { LS } = 0.99 _ { -0.54 } ^ { +0.91 } ~ { } { kpc } , implying that this is a brown-dwarf/Jupiter system that probably lies in the Galactic bulge , a location that is also consistent with the relatively low lens-source relative proper motion \mu = 3.2 \pm 0.5 ~ { } { mas } ~ { } { yr ^ { -1 } } .
The projected companion-host separation is 0.59 _ { -0.11 } ^ { +0.12 } ~ { } { AU } , indicating that the planet is placed beyond the snow line of the host , i.e. , a _ { sl } \sim 0.12 ~ { } { AU } .
Planet formation scenarios combined with the small companion-host mass ratio q \sim 0.016 and separation suggest that the companion could be the first discovery of a giant planet that formed in a protoplanetary disk around a brown dwarf host .