The MOSDEF Survey: First Measurement of Nebular Oxygen Abundance at $z>4$

Understand

We present the first spectroscopic measurement of multiple rest-frame optical emission lines at $z>4$.

• During the MOSFIRE Deep Evolution Field (MOSDEF) survey, we observed the galaxy GOODSN-17940 with the Keck I/MOSFIRE spectrograph.
• The K-band spectrum of GOODSN-17940 includes significant detections of the [OII]$\lambda\lambda 3726,3729$, [NeIII]$\lambda3869$, and H$\gamma$ emission lines and a tentative detection of H$\delta$, indicating $z_{\rm{spec}}=4.4121$.
• GOODSN-17940 is an actively star-forming $z>4$ galaxy based on its K-band spectrum and broadband spectral energy distribution.