  Extended, soft X-ray emission from the halo of a very large disk galaxy has
been detected out to r~20-40 kpc. The luminosity and surface brightness
distribution is in very good agreement with predictions by recent, cosmological
galaxy formation models. Predictions of Ly-alpha emission, associated with
``cold'' accretion of filamentary gas onto galaxies, are presented. In
particular these predictions are compared to the properties of a recently
detected Ly-alpha ``blob'', which shows no obvious continuum counter-part in
any of 12 broad-bands, from X-rays (Chandra) to infrared (Spitzer). Finally,
the predicted evolution of the Tully-Fisher relation, going from z=0 to 1, is
discussed in relation to recent observations.
