We present multi-epoch non-redundant masking observations of the T Cha
transition disk, taken at the VLT and Magellan in H, Ks, and L' bands. T Cha is
one of a small number of transition disks that host companion candidates
discovered by high-resolution imaging techniques, with a putative companion at
a position angle of 78 degrees, separation of 62 mas, and contrast at L' of 5.1
mag. We find comparable binary parameters in our re-reduction of the initial
detection images, and similar parameters in the 2011 L', 2013 NaCo L', and 2013
NaCo Ks data sets. We find a close-in companion signal in the 2012 NaCo L'
dataset that cannot be explained by orbital motion, and a non-detection in the
2013 MagAO/Clio2 L' data. However, Monte-carlo simulations show that the best
fits to the 2012 NaCo and 2013 MagAO/Clio2 followup data may be consistent with
noise. There is also a significant probability of false non-detections in both
of these data sets. We discuss physical scenarios that could cause the best
fits, and argue that previous companion and scattering explanations are
inconsistent with the results of the much larger dataset presented here.Comment: 25 pages, 22 figures, accepted for publication in Ap