  The structure of the outskrits of galaxies provides valuable information
about their past and evolution. Due to their projected orientation, edge-on
isolated galaxies effectively serve as test labs in which to study the
three-dimensional structures of galaxies including warps and flares, and to
explore the possible sources of souch distortions. We analyzed the structure of
the apparently isolated edge-on ultra-thin galaxy UGC11859 to look for the
presence of disortions. The deep optical imaging observations we acquired with
the GTC (Gran Telescopio Canarias) are used to derive the radial and vertical
surface brightness profiles and g-r color radial profile. We find that the
galaxy disk display a significant gravitational distortion. A warp is clearly
detected on one side of the disk, and the galactic plane on both sides of the
centre shows increasing scale height with increasing galactocentric radius,
indicating the presence of a flare in the stellar distribution. The surface
brightness profile of the disk shows a sharp break at 24 kiloparsecs
galactocentric radius, and a steep decline to larger radii, and edge-on
truncation, which we associate with the presence of the flare. The present
study is the first observational support for a connection between truncations
and flares. Just beyond the warped side of the disk a faint galaxy is observed
within a small angular distance, identified as a potential interacting
companion. Bases on ultra-deep g and r photometry we estimate that if the
potential companion is at the same distance as UGC11859, the stellar mas of the
satellite galaxy is approximately 6.33 log(MSol)
