On 2019 August 14 the Laser Interferometer Gravitational Wave Observatory ( LIGO ) and the Virgo gravitational wave interferometer announced the detection of a binary merger , S190814bv , with a low false alarm rate ( FAR ) of about 1 in 1.6 \times 10 ^ { 25 } yr , a distance of 267 \pm 52 Mpc , a 90 % ( 50 % ) localization region of about 23 ( 5 ) deg ^ { 2 } , and a probability of being a neutron star–black hole ( NS–BH ) merger of > 99 \% . The LIGO/Virgo Collaboration ( LVC ) defines NS–BH such that the lighter binary member has a mass of < 3 M _ { \odot } and the more massive one has > 5 M _ { \odot } , and this classification is in principle consistent with a BH–BH merger depending on the actual upper mass cutoff for neutron stars . Additionally , the LVC designated a probability that the merger led to matter outside the final BH remnant of < 1 \% , suggesting that an electromagnetic ( EM ) counterpart is unlikely . Here we report our optical follow-up observations of S190814bv using the Magellan Baade 6.5 m telescope to target all 96 galaxies in the Galaxy List for the Advanced Detector Era catalog within the 50 % localization volume ( representing about 70 % of the integrated luminosity within this region ) . No counterpart was identified to a median 3 \sigma limiting magnitude of i = 22.2 ( M _ { i } \approx - 14.9 mag ) , comparable to the brightness of the optical counterpart of the binary neutron star merger GW170817 at the distance of S190814bv ; similarly , we can rule out an on-axis jet typical of short GRBs . However , we can not rule out other realistic models , such as a kilonova with only \sim 0.01 M _ { \odot } of lanthanide-rich material , or an off-axis jet with a viewing angle of \theta _ { obs } \gtrsim 15 ^ { \circ } .