We report on our first set of spectroscopic Hubble Space Telescope observations of the z~11 candidate galaxy strongly lensed by the MACSJ0647.7+7015 galaxy cluster. The three lensed images are faint and we show that these early slitless grism observations are of sufficient depth to investigate whether this high-redshift candidate, identified by its strong photometric break at ~1.5 micron, could possibly be an emission line galaxy at a much lower redshift. While such an interloper would imply the existence of a rather peculiar object, we show here that such strong emission lines would clearly have been detected. Comparing realistic, two-dimensional simulations to these new observations we would expect the necessary emission lines to be detected at >5 sigma while we see no evidence for such lines in the dispersed data of any of the three lensed images. We therefore exclude that this object could be a low redshift emission line interloper, which significantly increases the likelihood of this candidate being a bona fide z~11 galaxy.
@article{arxiv.1502.05681,
title = {Not In Our Backyard: Spectroscopic Support for the CLASH z=11 Candidate MACS0647-JD},
author = {Nor Pirzkal and Dan Coe and Brenda L. Frye and Gabriel Brammer and John Moustakas and Barry Rothberg and Thomas J. Broadhurst and Rychard Bouwens and Larry Bradley and Arjen van der Wel and Daniel D. Kelson and Megan Donahue and Adi Zitrin and Leonidas Moustakas and Elizabeth Barker},
journal= {arXiv preprint arXiv:1502.05681},
year = {2015}
}
Comments
14 Pages. 6 Figures. 2nd revised version. Accepted. To appear in ApJ. Please contact [email protected] for comments on this paper