The binary companion of PSR J1740−3052

We report on the identification of a near-infrared counterpart to the massive (>11 M⊙) binary companion of pulsar J1740−3052. An accurate celestial position of PSR J1740−3052 is determined from interferometric radio observations. Adaptive optics corrected near-infrared imaging observations show a counterpart at the interferometric position of the pulsar. The counterpart has Ks= 15.87 ± 0.10 and J−Ks > 0.83. Based on distance and absorption estimates from models of the Galactic electron and dust distributions, these observed magnitudes are consistent with those of a main-sequence star as the binary companion. We argue that this counterpart is the binary companion to PSR J1740−3052 and thus rule out a stellar mass black hole as the pulsar companion.