  The X-ray properties of the haloes of disk galaxies formed in fully
cosmological, hydro/gravity simulations are discussed. The results are found to
be consistent with observational X-ray detections and upper limits. Disk galaxy
haloes are predicted to be about an order of magnitude brighter in soft X-rays
at z~1 than at z=0. The Ly-alpha and H-alpha surface brightness of an edge-on,
Milky Way like model galaxy has been determined. The emission is found to be
quite extended, with a scale height of about 600 pc, neglecting extinction
corrections.
