Near-Pristine Gas at High Redshifts: First Stars, Big-Bang Nucleosynthesis, and Limits on Dark Radiation - a podcast by Michael Haack

In this seminar, I shall describe recent work by our group on iden- tifying pockets of gas at high redshift that have undergone mini- mum processing through stars. The chemical composition of such gas still bears the imprints of the first few generations of stars that formed only a few hundred million years after the Big Bang, and thereby gives us clues to the physical properties of these still mys- terious objects which heralded the so-called ‘epoch of reionisation’. Near-pristine gas at high redshift is also the astrophysical environ- ment where the primordial abundance of deuterium can be measured most precisely. I will show how determinations of the cosmic den- sity of baryons from Big-Bang Nucleosynthesis and from the Cosmic Microwave Background have now reached comparable precision, in both cases of order of a few percent. The excellent agreement be- tween these two measures at widely different cosmic epochs places interesting limits on the existence of relativistic particles beyond the standard model of physics.

Further episodes of Sommerfeld Theory Colloquium (ASC)

Further podcasts by Michael Haack

Website of Michael Haack