To Illuminate the Dark Ages

Wed 5th June, 2019 @14:15 PM, level 7, David Caro Building
Dr Yuxiang Qin, Scuola Normale Superiore, Pisa



The measurement of the cosmic 21-cm signal with the SKA will transform our understanding of the epochs of reionization and cosmic dawn. The properties of the first stars and galaxies are encoded in the patterns of the signal. Interpreting these patterns requires accurate and efficient models. I will present an update of the 21cmFAST semi-numerical simulation, which separately accounts for star-formation inside the very first galaxies. This unseen and transient population of galaxies obtain their gas through molecular cooling from the intergalactic medium, and could have markedly different properties from the more massive galaxies observed with Hubble and eventually JWST. I demonstrate that if the recently-reported EDGES signal at z~17 is genuinely cosmological, these molecularly-cooled “mini-halo” galaxies must have played a dominant role during Cosmic Dawn.