In addition to detecting vast numbers of HI emission line galaxies, the SKA can also perform the deepest ever radio continuum survey, probing the star formation history of the Universe as a function of redshift in a manner independent of the dust extinction that confuses experiments in optical wavebands.
It will be of great interest to link the star formation properties of galaxies to their HI contents, as a function of redshift and environment. Furthermore, a high resolution radio continuum survey over wide areas allows a precise measurement of the coherent shape distortions of distant galaxies imparted by the foreground cosmic web. This weak gravitational lensing encodes a vast body of cosmological information, and its exploitation will become one of our key cosmological probes within the next decade. Radio wavebands are particularly advantageous for this experiment because the point-spread function is well determined and stable (being simply the interferometer baseline distribution), solving the principle systematic difficulty inherent in the method.
Further information
Science with the Square Kilometre Array, New Astronomy Reviews, 2004
Galaxy evolution, cosmology and dark energy with the Square Kilometre Array
S.Rawlings, F.B. Abdalla, S.L Bridle, C.A.Blake, C.M. Baugh, L.J. Greenhill, J.M. van der Hulst
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