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OATS-UNI/TS SEMINAR
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Speaker: James Bolton (Univ. of Nottingham, UK)

Title: Reionisation via the Lyman-alpha line
Date: Wednesday, April 17th, 2013
Time: 11:30
Venue: Villa Bazzoni
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Abstract: The first luminous objects to form in the Universe produced ultra-violet photons which photo-ionised and heated the previously cold and neutral intergalactic medium (IGM). Observing the impact of the reionisation era on the IGM therefore provides us with an indirect probe of the formation and evolution of the first galaxies. Low frequency radio observations of the high redshift Universe will provide an exciting new window into this important epoch in the near future, but in the present the Lyman-alpha line (both in absorption and emission) can also inform us about the physical state of the high redshift IGM. In this talk I will briefly review existing observational constraints on the reionisation era, before going on to discuss new developments arising from observations of Lyman-alpha absorption around bright quasars at z=6-7 and the abundance of Lyman-alpha emitting galaxies approaching z=7. These measurements may be used to test existing theoretical models for reionisation, and can yield fresh insight into the timing of reionisation as well the nature of the first sources of light in the early Universe.
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Contact: Matteo Viel (OATs)