TY - JOUR
T1 - Early Results from GLASS-JWST. I
T2 - Confirmation of Lensed z ≥ 7 Lyman-break Galaxies behind the Abell 2744 Cluster with NIRISS
AU - Roberts-Borsani, Guido
AU - Morishita, Takahiro
AU - Treu, Tommaso
AU - Brammer, Gabriel
AU - Strait, Victoria
AU - Wang, Xin
AU - Bradac, Marusa
AU - Acebron, Ana
AU - Bergamini, Pietro
AU - Boyett, Kristan
AU - Calabró, Antonello
AU - Castellano, Marco
AU - Fontana, Adriano
AU - Glazebrook, Karl
AU - Grillo, Claudio
AU - Henry, Alaina
AU - Jones, Tucker
AU - Malkan, Matthew
AU - Marchesini, Danilo
AU - Mascia, Sara
AU - Mason, Charlotte
AU - Mercurio, Amata
AU - Merlin, Emiliano
AU - Nanayakkara, Themiya
AU - Pentericci, Laura
AU - Rosati, Piero
AU - Santini, Paola
AU - Scarlata, Claudia
AU - Trenti, Michele
AU - Vanzella, Eros
AU - Vulcani, Benedetta
AU - Willott, Chris
N1 - Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/10/1
Y1 - 2022/10/1
N2 - We present the first search for z ≥ 7, continuum-confirmed Lyman break sources with NIRISS/WFS spectroscopy over the Abell 2744 Frontier Fields cluster, as part of the GLASS-JWST-ERS survey. With ∼15 hr of preimaging and multiangle grism exposures in the F115W, F150W, and F200W filters, we describe the general data handling (i.e., reduction, cleaning, modeling, and extraction processes) and analysis for the GLASS-JWST survey. We showcase the power of JWST to peer deep into reionization, when most intergalactic hydrogen is neutral, by confirming two galaxies at z = 8.04 ± 0.15 and z = 7.90 ± 0.13 by means of their Lyman breaks. Fainter continuum spectra are observed in both the F150W and F200W bands, indicative of blue (−1.69 and −1.33) UV slopes and moderately bright absolute magnitudes (−20.37 and −19.68 mag). We do not detect strong Lyα in either galaxy, but do observe tentative (∼2.7-3.8σ) He ii λ1640 Å, O iii]λλ1661,1666 Å, and N iii]λλ1747,1749 Å line emission in one, suggestive of low-metallicity, star-forming systems with possible nonthermal contributions. These novel observations provide a first look at the extraordinary potential of JWST/NIRISS for confirming representative samples of bright z ≥ 7 sources in the absence of strong emission lines, and gain unprecedented insight into their contributions toward cosmic reionization.
AB - We present the first search for z ≥ 7, continuum-confirmed Lyman break sources with NIRISS/WFS spectroscopy over the Abell 2744 Frontier Fields cluster, as part of the GLASS-JWST-ERS survey. With ∼15 hr of preimaging and multiangle grism exposures in the F115W, F150W, and F200W filters, we describe the general data handling (i.e., reduction, cleaning, modeling, and extraction processes) and analysis for the GLASS-JWST survey. We showcase the power of JWST to peer deep into reionization, when most intergalactic hydrogen is neutral, by confirming two galaxies at z = 8.04 ± 0.15 and z = 7.90 ± 0.13 by means of their Lyman breaks. Fainter continuum spectra are observed in both the F150W and F200W bands, indicative of blue (−1.69 and −1.33) UV slopes and moderately bright absolute magnitudes (−20.37 and −19.68 mag). We do not detect strong Lyα in either galaxy, but do observe tentative (∼2.7-3.8σ) He ii λ1640 Å, O iii]λλ1661,1666 Å, and N iii]λλ1747,1749 Å line emission in one, suggestive of low-metallicity, star-forming systems with possible nonthermal contributions. These novel observations provide a first look at the extraordinary potential of JWST/NIRISS for confirming representative samples of bright z ≥ 7 sources in the absence of strong emission lines, and gain unprecedented insight into their contributions toward cosmic reionization.
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U2 - 10.3847/2041-8213/ac8e6e
DO - 10.3847/2041-8213/ac8e6e
M3 - Article
AN - SCOPUS:85141280755
SN - 2041-8205
VL - 938
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L13
ER -