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The detection of the expected sources of the reionization of the Universe is one of the prominent MOSAIC science case. We simulated the detection of UV interstellar lines at z = 7 and the detection of the Ly-alpha line and the Lyman break at z = 9, both with MOAO-assisted IFUs and GLAO-fed fibers. The simulations show that the most constraining case is the detection of UV interstellar lines. The optimal pixel size is found to be ~80 mas, which allows detecting UV lines up to JAB ~ 27 in 40 hours of integration time. Lyman Alpha Emitters and Lyman Break Galaxies are detected respectively up to JAB ~ 29-30 and JAB ~ 28 with an 80 mas/pixel IFU and within only 10 hours of integration time. Detection limits are typically ~ 0.5-1 mag fainter using MOAO-fed IFUs than using GLAO-fed fibers, but the multiplex is one magnitude larger in the mode using GLAO-fed fibers. Further details can be found in Disseau et al. (2014).


Simulated IFU observations of z~9, JAB=29 Lyman Alpha Emitters. Top panel: an integrated spectrum was constructed from the simulated IFU observations. The resulting spectrum shows the line can be detected after a 10 hr exposure time with MOSAIC IFUs on the ELT. Bottom panel: same simulations using a 0.4 arcsec mono-fiber aperture.

Upper panel: z~10 candidate in the Hubble Ultra Deep FIeld (Bouwens et al. 2011). Lower panel: Planned followup of the z~10 candidate with the MOSAIC IFU (left). The expected spectra of the candidate as observed by MOSAIC at ELT in 10h of integration time is shown ih the lower right panel (Disseau et al. 2014).

Adapted from Hubble Ultra Deep Field 2009-2010 and UDFj-39546284. Credit: NASA, ESA, G. Illingworth (University of California, Santa Cruz), R. Bouwens (University of California, Santa Cruz, and Leiden University), and the HUDF09 Team.