X-rays from disk galaxy halos, lyα from forming galaxies, and thez∼1 tully-fisher relation

Abstract

Extended, soft X-ray emission from the halo of a very large disk galaxy has been detected. The luminosity and surface brightness distribution is in excellent agreement with predictions by recent, cosmological galaxy formation models. Predicted Lyα emission, associated with “cold” accretion of filamentary gas onto galaxies, is discussed in relation to Lyα “blobs”. Finally, the predicted evolution of the Tully-Fisher relation, going from z=0 to 1, is discussed in relation to recent observations.