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 iiλ1640 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.

Early Results from GLASS-JWST. I: Confirmation of Lensed z ≥ 7 Lyman-break Galaxies behind the Abell 2744 Cluster with NIRISS [Early Results from GLASS-JWST. I: Confirmation of Lensed z >= 7 Lyman-break Galaxies behind the Abell 2744 Cluster with NIRISS] / G. Roberts-Borsani, T. Morishita, T. Treu, G. Brammer, V. Strait, X. Wang, M. Bradac, A. Acebron Munoz, P. Bergamini, K. Boyett, A. Calabró, M. Castellano, A. Fontana, K. Glazebrook, C. Grillo, A. Henry, T. Jones, M. Malkan, D. Marchesini, S. Mascia, C. Mason, A. Mercurio, E. Merlin, T. Nanayakkara, L. Pentericci, P. Rosati, P. Santini, C. Scarlata, M. Trenti, E. Vanzella, B. Vulcani, C. Willott. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - 938:2(2022 Oct 18), pp. L13.1-L13.7. [10.3847/2041-8213/ac8e6e]

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

A. Acebron Munoz;P. Bergamini;C. Grillo;
2022

Abstract

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 iiλ1640 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.
high-redshift galaxies; star formation; cosmology; dark ages; reionization; first stars
Settore FIS/05 - Astronomia e Astrofisica
PRIN201719CGRIL_01 - Zooming into Dark Matter and proto-galaxies with massive lensing clusters - GRILLO, CLAUDIO - PRIN2017 - PRIN bando 2017 - 2019
PRIN202022CGRIL_01 - GRAvitational lensing in galaxy clusters next-generation proposAL - GRILLO, CLAUDIO - PRIN2020 - PRIN bando 2020 - 2022
18-ott-2022
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/949515
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