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Out of this world: exploring the Universe with the largest emission-line surveys
  Astronomy and astrophysics

Friday 22 April 2016
from 10:30 to 11:30
at FC61
Speaker : David Sobral (Lancaster University)
Abstract : I will present new results regarding the first 2 Gyrs of cosmic time using very wide-field Lyman-alpha narrow-band surveys, including a large, matched Lya-Ha survey at z=2.23 to calibrate Lyman-alpha (CALYMHA). We are currently conducting and exploring unique ~10 deg2 NB surveys with CFHT, Subaru and the INT to look for Lyman-alpha emitters at z=2.23-8.8. Surprisingly, we find a much higher space density of luminous Lyman-alpha emitters at z~6-7 than previously assumed, which we confirm spectroscopically with Keck and the VLT and that may be powered by unseen stellar populations (“PopIII-like”) or direct collapse black holes. Our unique samples include sources even more luminous in Lyman-alpha than Himiko at z=6.6 (e.g. our CR7 galaxy), showing that ultra-luminous Lyman-alpha emitters are much more common than thought at z~6.6. Our results have important consequences for our understanding of re-ionisation and are highly relevant for what J-PAS and EUCLID may be able to recover by conducting ultra-wide surveys.

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