Large Binocular Telescope observations of PSR J2043+2740

We present the results of deep optical imaging of the radio/gamma-ray pulsar PSR J2043+2740, obtained with the Large Binocular Telescope (LBT). With a characteristic age of 1.2Myr, PSR J2043+2740 is one of the oldest (non-recycled) pulsars detected in gamma-rays, although with still a quite high rotational energy reservoir (E-rot = 5.6 x 10(34) erg s(-1)). The presumably close distance (a few hundred pc), suggested by the hydrogen column density (N-H less than or similar to 3.6 x 10(20) cm(-2)), would make it a viable target for deep optical observations, never attempted until now. We observed the pulsar with the Large Binocular Camera of the LBT. The only object (V = 25.44 +/- 0.05) detected within similar to 3 arcsec from the pulsar radio coordinates is unrelated to it. PSR J2043+2740 is, thus, undetected down to V similar to 26.6 (3s), the deepest limit on its optical emission. We discuss the implications of this result on the pulsar emission properties.