NGC 5907 revisited: a stellar halo formed by cannibalism?
  We report on further observations of the luminous halo of NGC 5907. New V, I and B deep photometry confirms the existence of an extended stellar halo redder than the disk. Our data are consistent with a faint halo, or very thick disk, composed of a metal-rich old stellar population. We propose that it could be the remnant of a merged small elliptical, and we support our hypothesis with N-body simulations. 
J. Lequeux, F. Combes, M. Dantel-Fort, J.-C. Cuillandre, B. Fort and   Y. Mellier