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arXiv · 1502.05681

Not In Our Backyard: Spectroscopic Support for the CLASH z=11 Candidate MACS0647-JD

Nor Pirzkal·Dan Coe·Brenda L. Frye·Gabriel Brammer·John Moustakas·Barry Rothberg·Thomas J. Broadhurst·Rychard Bouwens·Larry Bradley·Arjen van der Wel·Daniel D. Kelson·Megan Donahue·Adi Zitrin·Leonidas Moustakas·Elizabeth Barker
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Abstract

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.

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Nor Pirzkal, Dan Coe, Brenda L. Frye, Gabriel Brammer, John Moustakas, Barry Rothberg, Thomas J. Broadhurst, Rychard Bouwens, Larry Bradley, Arjen van der Wel, Daniel D. Kelson, Megan Donahue, Adi Zitrin, Leonidas Moustakas, Elizabeth Barker. 2015-02-22. Not In Our Backyard: Spectroscopic Support for the CLASH z=11 Candidate MACS0647-JD. https://doi.org/10.1088/0004-637x%2F804%2F1%2F11

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