X-ray, Ly-alpha and H-alpha Emission from Simulated Disk Galaxies

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.