Probing the very first galaxies with the SKA

Abstract

We describe the use of the high redshift 21 cm signal to probe the very first galaxies to appear in the Universe. Using fast large volume simulations of the pre-Reionization epoch we have shown that the Lyman alpha radiation emitted from these young galaxies makes a strong contribution to the 21cm signal on large scales at z∼20. With the current setup the Square Kilometre Array (SKA) should be able to measure this signal, therefore making it probably the only telescope capable of giving us detailed information about the radiation emitted by the first stars and characterizing their host galaxies. SKA-pathfinders with ∼10%of the full collecting area should be capable of making a statistical detection of the 21cm power spectrum at redshifts z<20.We then discuss the use of the redshift space distortions as a way to further constrain the Lyman alpha signal and demonstrate that they can be used as a model independent way to extract this signature with the SKA. © Springer-Verlag Berlin Heidelberg 2012.