%0 Generic %1 shapley2017mosdef %A Shapley, Alice E. %A Sanders, Ryan L. %A Reddy, Naveen A. %A Kriek, Mariska %A Freeman, William R. %A Mobasher, Bahram %A Siana, Brian %A Coil, Alison L. %A Leung, Gene C. K. %A deGroot, Laura %A Shivaei, Irene %A Price, Sedona H. %A Azadi, Mojegan %A Aird, James %D 2017 %K galaxies high metallicity redshift %T The MOSDEF Survey: First Measurement of Nebular Oxygen Abundance at $z>4$ %U http://arxiv.org/abs/1707.05331 %X 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$łambda3726,3729$, NeIII$łambda3869$, and H$\gamma$ emission lines and a tentative detection of H$\delta$, indicating $z_spec=4.4121$. GOODSN-17940 is an actively star-forming $z>4$ galaxy based on its K-band spectrum and broadband spectral energy distribution. A significant excess relative to the surrounding continuum is present in the Spitzer/IRAC channel 1 photometry of GOODSN-17940, due primarily to strong H$\alpha$ emission with a rest-frame equivalent width of $EW(H\alpha)=1200$ \AA. Based on the assumption of $0.5 Z_ødot$ models and the Calzetti attenuation curve, GOODSN-17940 is characterized by $M_*=510^9 M_ødot$. The Balmer decrement inferred from H$\alpha$/H$\gamma$ is used to dust correct the H$\alpha$ emission, yielding $SFR(H\alpha)=320 M_ødot yr^-1$. These $M_*$ and SFR values place GOODSN-17940 an order of magnitude in SFR above the $z4$ star-forming "main sequence." Finally, we use the observed ratio of NeIII/OII to estimate the nebular oxygen abundance in GOODSN-17940, finding $O/H0.2 (O/H)_ødot$. Combining our new NeIII/OII measurement with those from stacked spectra at $z0, 2, and 3$, we show that GOODSN-17940 represents an extension to $z>4$ of the evolution towards higher NeIII/OII (i.e., lower $O/H$) at fixed stellar mass. It will be possible to perform the measurements presented here out to $z\sim 10$ using the James Webb Space Telescope.

@misc{shapley2017mosdef, abstract = {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. A significant excess relative to the surrounding continuum is present in the Spitzer/IRAC channel 1 photometry of GOODSN-17940, due primarily to strong H$\alpha$ emission with a rest-frame equivalent width of $\mbox{EW(H}\alpha)=1200$ \AA. Based on the assumption of $0.5 Z_{\odot}$ models and the Calzetti attenuation curve, GOODSN-17940 is characterized by $M_*=5\times 10^9 M_{\odot}$. The Balmer decrement inferred from H$\alpha$/H$\gamma$ is used to dust correct the H$\alpha$ emission, yielding $\mbox{SFR(H}\alpha)=320 M_{\odot}\mbox{ yr}^{-1}$. These $M_*$ and SFR values place GOODSN-17940 an order of magnitude in SFR above the $z\sim 4$ star-forming "main sequence." Finally, we use the observed ratio of [NeIII]/[OII] to estimate the nebular oxygen abundance in GOODSN-17940, finding $\mbox{O/H}\sim 0.2 \mbox{ (O/H)}_{\odot}$. Combining our new [NeIII]/[OII] measurement with those from stacked spectra at $z\sim 0, 2, \mbox{ and } 3$, we show that GOODSN-17940 represents an extension to $z>4$ of the evolution towards higher [NeIII]/[OII] (i.e., lower $\mbox{O/H}$) at fixed stellar mass. It will be possible to perform the measurements presented here out to $z\sim 10$ using the James Webb Space Telescope.}, added-at = {2017-07-19T10:44:19.000+0200}, author = {Shapley, Alice E. and Sanders, Ryan L. and Reddy, Naveen A. and Kriek, Mariska and Freeman, William R. and Mobasher, Bahram and Siana, Brian and Coil, Alison L. and Leung, Gene C. K. and deGroot, Laura and Shivaei, Irene and Price, Sedona H. and Azadi, Mojegan and Aird, James}, biburl = {https://www.bibsonomy.org/bibtex/28bcb037b979f0f4bf6bd1d7ce41a9822/miki}, description = {[1707.05331] The MOSDEF Survey: First Measurement of Nebular Oxygen Abundance at $z>4$}, interhash = {299ffb13fb4dee3e3a5120e402e456bb}, intrahash = {8bcb037b979f0f4bf6bd1d7ce41a9822}, keywords = {galaxies high metallicity redshift}, note = {cite arxiv:1707.05331Comment: 6 pages, 3 figures, submitted to ApJ Letters}, timestamp = {2017-07-19T10:44:19.000+0200}, title = {The MOSDEF Survey: First Measurement of Nebular Oxygen Abundance at $z>4$}, url = {http://arxiv.org/abs/1707.05331}, year = 2017 }