Gemini H-band imaging of the field of a z=10 candidate

We present a deep H-band image of the field of a candidate z = 10 galaxy magnified by the foreground (z = 0.25) cluster A1835. The image was obtained with NIRI on Gemini-North to better constrain the photometry and investigate the morphology of the source. The image is approximately 1 mag deeper and has better spatial resolution (seeing was 0".4-0".5) than the existing H-band image obtained with ISAAC on the Very Large Telescope by Pello et al. The object is not detected in our new data. Given the published photometry (H-AB = 25.0), we would have expected it to have been detected at more than similar to7 sigma in a 1".4 diameter aperture. We obtain a limit of H-AB > 26.0 (3 sigma) for the object. A major part of the evidence that this object is at z = 10 was the presence of a strong continuum break between the J and H bands, attributed to absorption of all continuum shortward of 1216 Angstrom in the rest frame of the object. Our H-band nondetection substantially reduces the magnitude of any break and therefore weakens the case that this object is at z =10. Without a clear continuum break, the identification of an emission line at 1.33745 mum as Lyalpha at z approximate to 10 is less likely. We show that the width and flux of this line are consistent with an alternative emission line such as [O III] lambda5007 from an intermediate-redshift H II/dwarf galaxy.