Optical and Infrared Nondetection of the z = 10 Galaxy behind Abell 1835

Abstract

Gravitational lensing by massive galaxy clusters is a powerful tool for the discovery and study of high-redshift galaxies, including those at z>=6 likely responsible for cosmic reionization. Pelló et al. recently used this technique to discover a candidate gravitationally magnified galaxy at z=10 behind the massive cluster lens Abell 1835 (z=0.25). We present new Keck and Spitzer Space Telescope observations of the z=10 candidate (hereafter #1916, following Pelló et al.'s nomenclature) together with a reanalysis of archival optical and near-infrared imaging from the Hubble Space Telescope and Very Large Telescope, respectively. Our analysis extends from the atmospheric cutoff at λ_obs~=0.35 μm out to λ_obs~=5 μm. The z=10 galaxy is not detected in any of these data, including an independent reduction of Pelló et al.'s discovery H- and K-band imaging. We conclude that there is no statistically reliable evidence for the existence of #1916. We also assess the implications of our results for ground-based near-infrared searches for gravitationally magnified galaxies at z>~7. The broad conclusion is that such experiments remain feasible, assuming that space-based optical and mid-infrared imaging are available to break the degeneracy with low-redshift interlopers (e.g., z~2-3) when fitting spectral templates to the photometric data.