Galaxies in the early Universe might grow through the accretion of cold, primordial, low-metallicity gas. If such gas is funnelled to the centre of a galaxy, it will result in the central region having an overall lower metallicity than outer regions. These authors report such 'inverse' metallicity gradients in three rotationally supported, star-forming galaxies at redshift ∼3, and conclude that the central gas has been diluted by the accretion of primordial gas.
- G. Cresci
- F. Mannucci
- L. Magrini
