A Remarkably Luminous Galaxy at Z = 11.1 Measured with Hubble Space Telescope


We present Hubble WFC3/IR slitless grism spectra of a remarkably bright z & 10 galaxy candidate, GN-z11, identified initially from CANDELS/GOODS-N imaging data. A significant spectroscopic continuum break is detected at λ = 1.47 ± 0.01 μm. The new grism data, combined with the photometric data, rule out all plausible lower redshift solutions for this source. The only viable solution is that this continuum break is the Lyα break redshifted to zgrism = 11.09 +0.08 −0.12, just ∼400 Myr after the Big Bang. This observation extends the current spectroscopic frontier by 150 Myr to well before the Planck (instantaneous) cosmic reionization peak at z ∼ 8.8, demonstrating that galaxy build-up was well underway early in the reionization epoch at z > 10. GN-z11 is remarkably and unexpectedly luminous for a galaxy at such an early time: its UV luminosity is 3× larger than L∗ measured at z ∼ 6− 8. The Spitzer IRAC detections up to 4.5 μm of this galaxy are consistent with a stellar mass of ∼ 10 M . This spectroscopic redshift measurement suggests that the James Webb Space Telescope (JWST ) will be able to similarly and easily confirm such sources at z > 10 and characterize their physical properties through detailed spectroscopy. Furthermore, WFIRST, with its wide-field near-IR imaging, would find large numbers of similar galaxies and contribute greatly to JWST ’s spectroscopy, if it is launched early enough to overlap with JWST . Subject headings: galaxies: high-redshift — galaxies: formation — galaxies: evolution — dark ages, reionization, first stars

Cite this paper

@inproceedings{SPECTROSCOPY2016ARL, title={A Remarkably Luminous Galaxy at Z = 11.1 Measured with Hubble Space Telescope}, author={GRISM SPECTROSCOPY and Pascal A. Oesch and Gabriel B. Brammer and P. G. van Dokkum and Garth D . Illingworth and Rychard J . Bouwens and Ivo Labb{\'e} and Marijn Franx and Ivelina Momcheva and Matthew L. N. Ashby and Giovanni G. Fazio and Viridiana Gonz{\'a}lez and Brad P. Holden and Daniel K. Magee and R. E. Skelton and R. Smit and Lee R. Spitler and Michele Trenti and Steven P. Willner}, year={2016} }