[astroseminar at Sapienza] Seminar by Pratika Dayal, monday sept 16, 4 pm

[raffaella.schneider at roma1.infn.it]

Monday 16 September, 4 pm
Aula Rasetti, Physics Department
Speaker: Pratika Dayal (Kapteyn Institute, University of Groningen)

Title: Early galaxy formation and its large-scale effects

Galaxy formation in the first billion years mark a time of great upheaval in the history of the Universe: as the first sources of light, these galaxies ended the 'cosmic dark ages' and produced the first 
photons that could break apart the hydrogen atoms suffusing all of space starting the process of cosmic reionization. As the earliest building blocks, the galaxies that formed in the first billion years also
determine the physical properties of all subsequent galaxy populations. I will start by introducing the reionization process and detail the reasons foe which the history and topology of reionization 
remain debated. I will then show how cross-correlations of 21cm data with the underlying galaxy population, in the forthcoming era of 21cm cosmology, will yield tantalising constraints on the 
average intergalactic medium ionization state as well as the reionization topology (outside-in versus inside-out). Time permitting, I will try to give a flavour of how the assembly of early galaxies, 
accessible with the forthcoming James Webb Space Telescope, can provide a powerful testbed for Dark Matter models  beyond "Cold Dark Matter".