JWST NIRSpec High-resolution Spectroscopy of MACS0647–JD at z = 10.167: Resolved [O II] Doublet and Electron Density in an Early Galaxy
Hutchison, Taylor A.; Larson, Rebecca L.; Conselice, Christopher J.; Fujimoto, Seiji; Xu, Xinfeng; Mingozzi, Matilde; Jung, Intae; Álvarez-Márquez, Javier; Bik, Arjan; Gómez, Alejandro Crespo; Bhatawdekar, Rachana; Rigby, Jane R.; Zitrin, Adi; Coe, Dan; Windhorst, Rogier A.; Adamo, Angela; Norman, Colin; Bradley, Larry D.; Kokorev, Vasily; Dayal, Pratika; Furtak, Lukas J.; Vanzella, Eros; Welch, Brian; Diego, Jose M.; Hsiao, Tiger Yu-Yang; Abdurro'uf; Ricotti, Massimo; Killi, Meghana; Resseguier, Tom
United States, Spain, Sweden, United Kingdom, Netherlands, Israel, Chile, Italy
Abstract
We present JWST/NIRSpec high-resolution G395H/F290LP spectroscopy of MACS0647‑JD, a gravitationally lensed galaxy merger at z = 10.167. The new spectroscopy, which is acquired for the two lensed images (JD1 and JD2), detects and resolves emission lines in the rest-frame ultraviolet and blue optical, including the resolved [O II] λ λ3726, 3729 doublet, [Ne III] λ3870, He I λ3890, Hδ, Hγ, and [O III] λ4363. This is the first observation of the resolved [O II] λ λ3726, 3729 doublet for a galaxy at z > 8. We measure a line flux ratio [O II] λ3729/λ3726 = 0.9 ± 0.3, which corresponds to an estimated electron density of