GNHeII J1236+6215: A He II λ1640 Emitting and Potentially LyC Leaking Galaxy at z = 2.9803 Unveiled through JWST and Keck Observations
Chayan Mondal; Kanak Saha; Anshuman Borgohain; Brent Matthew Smith; Rogier A. Windhorst; Naveen A. Reddy; Chian-Chou Chen; Keiichi Umetsu · 2025 · The Astrophysical Journal
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Abstract
Abstract He II λ1640 emission in galaxies indicates the presence of sources that produce extreme ionizing photons. Here we report the discovery of a He II λ1640 emitting galaxy, GNHeII J1236+6215, at z = 2.9803 in the GOODS-north field. We use photometry in 17 wave bands from near-UV to infrared to characterize the galaxy spectral energy distribution (SED) and combine Keck Low-resolution Imaging Spectrometer and JWST NIRSpec spectra to identify 15 emission lines including He II λ1640. We infer that the He+ ionization in the galaxy could be driven by small pockets of young Population III stars
Abstract by Chayan Mondal; Kanak Saha; Anshuman Borgohain; Brent Matthew Smith; Rogier A. Windhorst; Naveen A. Reddy; Chian-Chou Chen; Keiichi Umetsu, The Astrophysical Journal (2025) — licensed CC BY 4.0.
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Metadata source: OpenAlex · DOI 10.3847/1538-4357/ade2cd