Texas Spectroscopic Search for Ly$alpha$ Emission at the End of Reionization II. The Deepest Near-Infrared Spectroscopic Observation at $zgtrsim7$. (arXiv:1901.05967v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Jung_I/0/1/0/all/0/1">Intae Jung</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Finkelstein_S/0/1/0/all/0/1">Steven L. Finkelstein</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Dickinson_M/0/1/0/all/0/1">Mark Dickinson</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Hutchison_T/0/1/0/all/0/1">Taylor A. Hutchison</a> (3), <a href="http://arxiv.org/find/astro-ph/1/au:+Larson_R/0/1/0/all/0/1">Rebecca L. Larson</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Papovich_C/0/1/0/all/0/1">Casey Papovich</a> (3), <a href="http://arxiv.org/find/astro-ph/1/au:+Pentericci_L/0/1/0/all/0/1">Laura Pentericci</a> (4), <a href="http://arxiv.org/find/astro-ph/1/au:+Song_M/0/1/0/all/0/1">Mimi Song</a> (5), <a href="http://arxiv.org/find/astro-ph/1/au:+Ferguson_H/0/1/0/all/0/1">Henry C. Ferguson</a> (6), <a href="http://arxiv.org/find/astro-ph/1/au:+Guo_Y/0/1/0/all/0/1">Yicheng Guo</a> (7), <a href="http://arxiv.org/find/astro-ph/1/au:+Malhotra_S/0/1/0/all/0/1">Sangeeta Malhotra</a> (5 and 8), <a href="http://arxiv.org/find/astro-ph/1/au:+Mobasher_B/0/1/0/all/0/1">Bahram Mobasher</a> (9) <a href="http://arxiv.org/find/astro-ph/1/au:+Rhoads_J/0/1/0/all/0/1">James Rhoads</a> (5 and 8), <a href="http://arxiv.org/find/astro-ph/1/au:+Tilvi_V/0/1/0/all/0/1">Vithal Tilvi</a> (8), <a href="http://arxiv.org/find/astro-ph/1/au:+Wold_I/0/1/0/all/0/1">Isak Wold</a> (5) ((1) UT Austin, (2) NOAO, (3) Texas A and M Univ., (4) INAF, (5) NASA Goddard, (6) STScI, (7) Univ. of Missouri, (8) Arizona State Univ., (9) UC Riverside)

Realizing the utility of Ly$alpha$ emission to trace the evolution of the
intergalactic medium (IGM) during the epoch of reionization requires deep
spectroscopy across the boundary of optical and near-infrared (NIR)
spectrographs at $zsim7.2$ when Ly$alpha$ emission is at $sim$1$mu$m. Our
Texas Spectroscopic Search for Ly$alpha$ Emission at the End of Reionization
includes 18 nights of deep spectroscopic observations using the Keck DEIMOS
(optical) and MOSFIRE (NIR) spectrographs. Within this dataset we observe
Ly$alpha$ emission from 183 photometric-redshift selected galaxies at $z =$
5.5 – 8.3 from the Cosmic Assembly Near infrared Deep Extragalactic Legacy
Survey (CANDELS). Our overlapping MOSFIRE observations, over 84 galaxies total,
provide the deepest NIR spectroscopic data yet obtained for Ly$alpha$ from
galaxies $z > 7$, with $>16$ hr integration time for four observed galaxies.
Here we analyze these four targets, and we report the discovery of a new $z =
7.60$ Ly$alpha$ detection as well as provide an updated observation of the
previously confirmed $z=7.51$ Ly$alpha$ emission from Finkelstein et al.
(2013) with a $sim$3$times$ longer exposure time. Our analysis of these
Ly$alpha$ emission line profiles reveal a significant asymmetric shape. The
two detected Ly$alpha$ emission lines from bright sources
($M_{text{UV}}<-20.25$) could imply that these bright galaxies inhabit ionized bubbles in a partially neutral IGM, although deeper exposures may yet reveal Ly$alpha$ emission in the fainter sources.

Realizing the utility of Ly$alpha$ emission to trace the evolution of the
intergalactic medium (IGM) during the epoch of reionization requires deep
spectroscopy across the boundary of optical and near-infrared (NIR)
spectrographs at $zsim7.2$ when Ly$alpha$ emission is at $sim$1$mu$m. Our
Texas Spectroscopic Search for Ly$alpha$ Emission at the End of Reionization
includes 18 nights of deep spectroscopic observations using the Keck DEIMOS
(optical) and MOSFIRE (NIR) spectrographs. Within this dataset we observe
Ly$alpha$ emission from 183 photometric-redshift selected galaxies at $z =$
5.5 – 8.3 from the Cosmic Assembly Near infrared Deep Extragalactic Legacy
Survey (CANDELS). Our overlapping MOSFIRE observations, over 84 galaxies total,
provide the deepest NIR spectroscopic data yet obtained for Ly$alpha$ from
galaxies $z > 7$, with $>16$ hr integration time for four observed galaxies.
Here we analyze these four targets, and we report the discovery of a new $z =
7.60$ Ly$alpha$ detection as well as provide an updated observation of the
previously confirmed $z=7.51$ Ly$alpha$ emission from Finkelstein et al.
(2013) with a $sim$3$times$ longer exposure time. Our analysis of these
Ly$alpha$ emission line profiles reveal a significant asymmetric shape. The
two detected Ly$alpha$ emission lines from bright sources
($M_{text{UV}}<-20.25$) could imply that these bright galaxies inhabit ionized
bubbles in a partially neutral IGM, although deeper exposures may yet reveal
Ly$alpha$ emission in the fainter sources.

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