Texas Spectroscopic Search for Lyα  Emission at the End of Reionization I. Constraining the Lyα  Equivalent-width Distribution at 6.0 &lt; z &lt; 7.0

Jung, Intae; Finkelstein, Steven L.; Livermore, Rachael; Dickinson, Mark; Larson, Rebecca L.; Papovich, Casey; Song, Mimi; Tilvi, Vithal; Wold, Isak

doi:10.3847/1538-4357/aad686

Cited by 37 publications

(45 citation statements)

References 190 publications

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“…both Lyα photons and ionizing radiation escaping through "holes" in the neutral ISM, similar to that discussed in Reddy et al (2016). Thus, understanding the intrinsic Lyα strength of high-redshift galaxies can provide important clues to the evolution of leaking ionizing radiation, and consequently the epoch of reionization (Jung et al 2018;Mason et al 2018;Laursen et al 2019).…”

Section: Discussionmentioning

confidence: 76%

The redshift evolution of rest-UV spectroscopic properties to z ∼ 5

Pahl

Shapley

Faisst

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We perform a comprehensive analysis of the redshift evolution of the rest-UV spectra of star-forming galaxies out to z ∼ 5. We combine new z ∼ 5 measurements of HI Lyα and low-and high-ionization interstellar metal absorption features with comparable measurements at z ∼ 2-4. This redshift range covers the peak epoch of star formation in the Universe and extends back towards the epoch of reionization. We measure the equivalent widths of interstellar absorption features using stacked spectra in bins of Lyα equivalent width, and perform corrections to the strength of Lyα based on a model for the transmission of the intergalactic medium. We find a strong trend of decreasing low-ionization line strength with increasing Lyα emission strength over the redshift range z ∼ 2-5, suggesting that both of these quantities are fundamentally linked to neutral gas covering fraction. At the highest Lyα equivalent widths, we see evolution with increasing redshift towards greater Lyα emission strength at fixed low-ionization absorption strength. This evolution suggests a higher intrinsic production rate of Lyα photons at z ∼ 5 than at lower redshift. Our conclusion is supported by the joint evolution of the relationships among Lyα emission strength, interstellar absorption strength, and dust reddening. We perform additional analysis in bins of stellar mass, star-formation rate, UV luminosity, and age, examining how the relationships between galaxy properties and Lyα emission evolve towards higher redshift. We conclude that increasing intrinsic Lyα photon production and strong detection of nebular C IV emission (signaling lower metallicity) at z ∼ 5 indicate an elevated ionized photon production efficiency (ξ ion ).

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Section: Discussionmentioning

confidence: 76%

The redshift evolution of rest-UV spectroscopic properties to z ∼ 5

Pahl

Shapley

Faisst

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…This consists of a total of 18 nights of spectroscopic observations targeting 183 galaxies at z > 5: for 118 galaxies with Keck/DEIMOS (PI: R. Livermore) and 84 galaxies with Keck/MOSFIRE (PI: S. Finkelstein; the majority coming through the NASA/Keck allocation). The entire program is described in Jung et al (2018) where we discuss our measure of the Lyα EW distribution at z ∼ 6.5 with DEIMOS. The target galaxies were selected from the Finkelstein et al (2015) photometric catalog.…”

Section: Texas Spectroscopic Search For Lyα Emission At the End Of Rementioning

confidence: 99%

Texas Spectroscopic Search for Lyα Emission at the End of Reionization. II. The Deepest Near-infrared Spectroscopic Observation at z ≳ 7

Jung

Finkelstein

Dickinson

et al. 2019

ApJ

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Realizing the utility of Lyα 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 z ∼ 7.2 when Lyα emission is at ∼1µm. Our Texas Spectroscopic Search for Lyα 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 Lyα emission from 183 photometricredshift 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 Lyα 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 Lyα detection as well as provide an updated observation of the previously confirmed z = 7.51 Lyα emission from Finkelstein et al. (2013) with a ∼3× longer exposure time. Our analysis of these Lyα emission line profiles reveal a significant asymmetric shape. The two detected Lyα emission lines from bright sources (M UV < −20.25) could imply that these bright galaxies inhabit ionized bubbles in a partially neutral IGM, although deeper exposures may yet reveal Lyα emission in the fainter sources. how galaxies and the intergalactic medium (IGM) interplay in the early universe. As the dominant sources of the ionizing photons are thought to be galaxies (e.g., Finkelstein et al. 2015;Robertson et al. 2015), investigating the evolution of the IGM during reionization provides critical constraints on the evolution of distant galax-

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“…We use these data to study the evolution as a function of both redshift and galaxy UV absolute magnitude. Section 2 describes the CLEAR high-z galaxy dataset (data reduction, sample selection, and emission-line and continuum-detection search) and the additional Keck DEIMOS and MOSFIRE observations from the Texas Spectroscopic Search for Lyα Emission at the End of Reionization Survey (Jung et al 2018(Jung et al , 2020, finalizing the 6.0 < z < 8.2 galaxy dataset for the Lyα analysis. In Section 3, we present our results, which includes the measurements of the Lyα EW distribution and the IGM transmission to Lyα.…”

Section: Introductionmentioning

confidence: 99%

CLEAR: Boosted Ly$α$ Transmission of the Intergalactic Medium in UV bright Galaxies

Jung,

Papovich,

Finkelstein

et al. 2021

Preprint

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Reionization is an inhomogeneous process, thought to begin in small ionized bubbles of the intergalactic medium (IGM) around overdense regions of galaxies. Recent Lyman-alpha (Lyα) studies during the epoch of reionization show growing evidence that ionized bubbles formed earlier around brighter galaxies, suggesting higher IGM transmission of Lyα from these galaxies. We investigate this problem using IR slitless spectroscopy from the Hubble Space Telescope (HST) Wide-Field Camera 3 (WFC3) G102 grism observations of 148 galaxies selected via photometric redshifts at 6.0 < z < 8.2. These galaxies have spectra extracted from the CANDELS Lyα Emission at Reionization (CLEAR) survey. We combine the CLEAR data for 275 galaxies with the Keck/DEIMOS+MOSFIRE dataset from the Texas Spectroscopic Search for Lyα Emission at the End of Reionization Survey. We then constrain the Lyα equivalent-width (EW) distribution at 6.0 < z < 8.2, which is described by an exponential form, dN/dEW ∝ exp(-EW)/W 0 , with the characteristic e-folding scale width (W 0 ). We confirm a significant drop of the Lyα strength (or W 0 ) at z > 6. Furthermore, we compare the redshift evolution of W 0 between galaxies at different UV luminosities. The UV-bright (M UV < −21, or L UV > L * ) galaxies show weaker evolution with a decrease of 0.4 (±0.2) dex in W 0 at z > 6 while UV-faint (M UV > −21, or L UV < L * ) galaxies exhibit a significant drop by a factor of 0.7-0.8 (±0.2) dex in W 0 from z < 6 to z > 6. Our results add to the accumulating evidence that UV-bright galaxies exhibit boosted Lyα transmission in the IGM, suggesting that reionization completes sooner in regions proximate to galaxies of higher UV luminosity.

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Texas Spectroscopic Search for Lyα Emission at the End of Reionization I. Constraining the Lyα Equivalent-width Distribution at 6.0 < z < 7.0

Cited by 37 publications

References 190 publications

The redshift evolution of rest-UV spectroscopic properties to z ∼ 5

The redshift evolution of rest-UV spectroscopic properties to z ∼ 5

Texas Spectroscopic Search for Lyα Emission at the End of Reionization. II. The Deepest Near-infrared Spectroscopic Observation at z ≳ 7

CLEAR: Boosted Ly$α$ Transmission of the Intergalactic Medium in UV bright Galaxies

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