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Early Results from GLASS-JWST. I: Confirmation of Lensed z ≥ 7 Lyman-break Galaxies behind the Abell 2744 Cluster with NIRISS

Roberts-Borsani, Guido and Morishita, Takahiro and Treu, Tommaso and Brammer, Gabriel and Strait, Victoria and Wang, Xin and Bradac, Marusa and Acebron, Ana and Bergamini, Pietro and Boyett, Kristan and Calabró, Antonello and Castellano, Marco and Fontana, Adriano and Glazebrook, Karl and Grillo, Claudio and Henry, Alaina and Jones, Tucker and Malkan, Matthew and Marchesini, Danilo and Mascia, Sara and Mason, Charlotte and Mercurio, Amata and Merlin, Emiliano and Nanayakkara, Themiya and Pentericci, Laura and Rosati, Piero and Santini, Paola and Scarlata, Claudia and Trenti, Michele and Vanzella, Eros and Vulcani, Benedetta and Willott, Chris (2022) Early Results from GLASS-JWST. I: Confirmation of Lensed z ≥ 7 Lyman-break Galaxies behind the Abell 2744 Cluster with NIRISS. Astrophysical Journal Letters, 938 (2). LArt. No. 13. ISSN 2041-8205. doi:10.3847/2041-8213/ac8e6e.

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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 ɪɪλ1640 Å, O ɪɪɪ]λλ1661,1666 Å, and N ɪɪɪ]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.

Item Type:Article
Related URLs:
URLURL TypeDescription
Roberts-Borsani, Guido0000-0002-4140-1367
Morishita, Takahiro0000-0002-8512-1404
Treu, Tommaso0000-0002-8460-0390
Brammer, Gabriel0000-0003-2680-005X
Strait, Victoria0000-0002-6338-7295
Wang, Xin0000-0002-9373-3865
Bradac, Marusa0000-0001-5984-0395
Acebron, Ana0000-0003-3108-9039
Bergamini, Pietro0000-0003-1383-9414
Boyett, Kristan0000-0003-4109-304X
Calabró, Antonello0000-0003-2536-1614
Castellano, Marco0000-0001-9875-8263
Fontana, Adriano0000-0003-3820-2823
Glazebrook, Karl0000-0002-3254-9044
Grillo, Claudio0000-0002-5926-7143
Henry, Alaina0000-0002-6586-4446
Jones, Tucker0000-0001-5860-3419
Malkan, Matthew0000-0001-6919-1237
Marchesini, Danilo0000-0001-9002-3502
Mascia, Sara0000-0002-9572-7813
Mason, Charlotte0000-0002-3407-1785
Mercurio, Amata0000-0001-9261-7849
Merlin, Emiliano0000-0001-6870-8900
Nanayakkara, Themiya0000-0003-2804-0648
Pentericci, Laura0000-0001-8940-6768
Rosati, Piero0000-0002-6813-0632
Santini, Paola0000-0002-9334-8705
Scarlata, Claudia0000-0002-9136-8876
Trenti, Michele0000-0001-9391-305X
Vanzella, Eros0000-0002-5057-135X
Vulcani, Benedetta0000-0003-0980-1499
Willott, Chris0000-0002-4201-7367
Additional Information:This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program JWST-ERS-1324. We acknowledge financial support from NASA through grant JWST-ERS-1324. K.G. and T.N. acknowledge support from Australian Research Council Laureate Fellowship FL180100060. C.M. acknowledges support by the VILLUM FONDEN under grant 37459. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant DNRF140. M.B. acknowledges support from the Slovenian national research agency ARRS through grant N1-0238. This research is supported in part by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project No. CE170100013. We acknowledge financial support through grants PRIN-MIUR 2017WSCC32 and 2020SKSTHZ.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASANAS 5-03127
Australian Research CouncilFL180100060
Villum Foundation37459
Danish National Research FoundationDNRF140
Australian Research CouncilCE170100013
Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR)2017WSCC32
Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR)2020SKSTHZ
Issue or Number:2
Record Number:CaltechAUTHORS:20221031-575177800.31
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:117667
Deposited By: Research Services Depository
Deposited On:09 Nov 2022 19:46
Last Modified:11 Nov 2022 18:05

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