2005MNRAS.357.1348W

We present a deep, narrow J-band search for protogalactic Lyα emission at redshifts z∼ 9. We combine an exceptionally deep image of the Hubble Deep Field South, obtained using a narrow-band filter centred on the wavelength 1.187 µm using the VLT/ISAAC facility, with existing deep, broad-band images covering optical to near-infrared wavelengths. We search for z∼ 9 Lyα-emitting galaxies displaying a significant narrow-band excess relative to the J_s band that are undetected at optical wavelengths. We detect no sources consistent with this criterion to the 90 per cent point-source flux limit of the narrow-band image, F_NB= 3.28 x10^–18 erg/s/cm2. The survey selection function indicates that we have sampled a volume of approximately 340h^–3 Mpc³ to a Lyα emission luminosity of 10⁴³h^–2/ergs. We conclude by considering the potential implications for the physics of the high-redshift Universe.