EUROPEAN SPACE AGENCY

JWST NIRSpec Spectroscopy of the Triply Lensed z = 10.17 Galaxy MACS0647–JD

DOI: 10.3847/1538-4357/ad5da8 Bibcode: 2024ApJ...973....8H

Hutchison, Taylor A.; Larson, Rebecca L.; Wilkins, Stephen M.; Donahue, Megan; Kumari, Nimisha; Broadhurst, Tom; Conselice, Christopher J.; Henry, Alaina; Bradač, Maruša; Fujimoto, Seiji; Xu, Xinfeng; Hernandez, Svea; James, Bethan L.; Mingozzi, Matilde; Brammer, Gabriel; Jung, Intae; Rigby, Jane R.; Zitrin, Adi; Coe, Dan; Andrade-Santos, Felipe; Windhorst, Rogier A.; Postman, Marc; Adamo, Angela; Pirzkal, Norbert; Norman, Colin; Bradley, Larry D.; Zackrisson, Erik; Kokorev, Vasily; Dayal, Pratika; Furtak, Lukas J.; Carnall, Adam C.; Vanzella, Eros; Welch, Brian; Diego, Jose M.; Hsiao, Tiger Yu-Yang; Abdurro'uf; Eldridge, Jan J.; Ricotti, Massimo; Antwi-Danso, Jacqueline; Vikaeus, Anton; Park, Hyunbae

United States, Netherlands, Sweden, Denmark, Israel, Canada, Slovenia, Spain, United Kingdom, New Zealand, Italy, Malta

Abstract

We present JWST/NIRSpec prism spectroscopy of MACS0647‑JD, a triply lensed z ∼ 11 candidate discovered in Hubble Space Telescope imaging and spatially resolved by JWST imaging into two components, A and B. Spectroscopy of component A yields a spectroscopic redshift z = 10.17 based on seven detected emission lines: C III] λ λ1907, 1909, [O II] λ3727, [Ne III] λ3869, [Ne III] λ3968, Hδ λ4101, Hγ λ4340, and [O III] λ4363. These are the second-most distant detections of these emission lines to date, in a galaxy observed just 460 million years after the Big Bang. Based on observed and extrapolated line flux ratios we derive a gas-phase metallicity 12 + log(O/H) ∼ 7.5–8.0, or Z ∼ (0.06–0.2) Z ⊙, ionization parameter log(U) = ‑1.9 ± 0.2, and an ionizing photon production efficiency log(ξion)=25.2±0.2 erg‑1 Hz. The spectrum has a softened Lyα break, evidence for a strong Lyα damping wing. The Lyα damping wing also suppresses the F150W photometry, explaining the slightly overestimated photometric redshift z = 10.6 ± 0.3. MACS0647‑JD has a stellar mass log(M/M ⊙) = 8.1 ± 0.3, including ∼6 × 107 M ⊙ in component A, most of which formed recently (within ∼20 Myr) with a star formation rate ∼ 2 ± 1 M ⊙ yr‑1, all within an effective radius 70 ± 24 pc. Spectroscopy of a fainter companion galaxy C separated by a distance of ∼ 3 kpc reveals a Lyman break consistent with z ∼ 10.17. MACS0647‑JD is likely the most distant galaxy merger known.

2024 • The Astrophysical Journal
Gaia JWST eHST 101
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