  The presence of stellar companions around planet hosting stars influences the
architecture of their planetary systems. To find and characterise these
companions and determine their orbits is thus an important consideration to
understand planet formation and evolution. For transiting systems even unbound
field stars are of interest if they are within the photometric aperture of the
light curve measurement. Then they contribute a constant flux offset to the
transit light curve and bias the derivation of the stellar and planetary
parameters if their existence is unknown. Close stellar sources are, however,
easily overlooked by common planet surveys due to their limited spatial
resolution. We therefore performed high angular resolution imaging of 49
transiting exoplanet hosts to identify unresolved binaries, characterize their
spectral type, and determine their separation. The observations were carried
out with the Calar Alto 2.2m telescope using the Lucky Imaging camera AstraLux
Norte. All targets were imaged in i' and z' passbands. We found new companion
candidates to WASP-14 and WASP-58, and we re-observed the stellar companion
candidates to CoRoT-2, CoRoT-3, CoRoT-11, HAT-P-7, HAT-P-8, HAT-P-41, KIC
10905746, TrES-2, TrES-4, and WASP-2. We deduce from the stellar density around
all sources that two companion candidates out of the targets with the first
position measurement (CoRoT-11, HAT-P-41, KIC 10905746, WASP-14 and WASP-58)
are probably unbound. In addition, we re-analyse the influence of the sources
close to WASP-14 and WASP-58 on the planetary parameters given in the
literature and find no significant changes.
