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J.J. Binney (Oxford University)
Semi-analytic galaxy-formation theory assumes that baryons conserve their angular momentum as they fall in to the centers of dark halos. Even so the theory predicts that galactic disks should be smaller than they actually are. Since early dark halos are expected to be lumpy and triaxial, baryons will in reality lose angular momentum as they fall in - numerical simulations strongly confirm this expectation. What becomes of low angular-momentum baryons? Some, but not all may form a spheroid. It is likely that the rest were ejected as a wind driven by a combination of the AGN and bulge. Thus galaxy formation, like star formation, may manifest itself more through bipolar outflow than detectable inflow. The ejected baryons could have significant impact on both later-infalling baryons and on the center of the dark-matter halo.