JADES NIRSpec Spectroscopy of GN-z11: Lyman-\(\alpha\) emission and possible enhanced nitrogen abundance in a \(z=10.60\) luminous galaxy

• Published in: arXiv.org 2023-05
• Main Authors: Bunker, Andrew J, Saxena, Aayush, Cameron, Alex J, Willott, Chris J, Curtis-Lake, Emma, Jakobsen, Peter, Carniani, Stefano, Smit, Renske, Maiolino, Roberto, Witstok, Joris, Curti, Mirko, D'Eugenio, Francesco, Jones, Gareth C, Ferruit, Pierre, Arribas, Santiago, Charlot, Stephane, Chevallard, Jacopo, Giardino, Giovanna, de Graaff, Anna, Looser, Tobias J, Luetzgendorf, Nora, Maseda, Michael V, Rawle, Tim, Hans-Walter Rix, Rodriguez Del Pino, Bruno, Alberts, Stacey, Egami, Eiichi, Eisenstein, Daniel J, Endsley, Ryan, Hainline, Kevin, Hausen, Ryan, Johnson, Benjamin D, Rieke, George, Rieke, Marcia, Robertson, Brant E, Shivaei, Irene, Stark, Daniel P, Sun, Fengwu, Tacchella, Sandro, Tang, Mengtao, Williams, Christina C, Willmer, Christopher N A, Baker, William M, Baum, Stefi, Bhatawdekar, Rachana, Bowler, Rebecca, Boyett, Kristan, Chen, Zuyi, Circosta, Chiara, Helton, Jakob M, Ji, Zhiyuan, Lyu, Jianwei, Nelson, Erica, Parlanti, Eleonora, Perna, Michele, Sandles, Lester, Scholtz, Jan, Suess, Katherine A, Topping, Michael W, Uebler, Hannah, Wallace, Imaan E B, Whitler, Lily
• Format: Article
• Language: English
• Subjects: Abundance; Active galactic nuclei; Cosmic dust; Galaxies; Helium isotopes; Ionization; Nitrogen; Photoionization; Red shift; Spectra; Spectroscopy; Spectrum analysis; Star & galaxy formation; Star formation rate
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2302.07256

We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminous candidate \(z>10\) Lyman break galaxy in the GOODS-North field with \(M_{UV}=-21.5\). We derive a redshift of \(z=10.603\) (lower than previous determinations) based on multiple emission lines in our low and medium resolution spectra over \(0.8-5.3 \mu\)m. We significantly detect the continuum and measure a blue rest-UV spectral slope of \(\beta=-2.4\). Remarkably, we see spatially-extended Lyman-\(\alpha\) in emission (despite the highly-neutral IGM expected at this early epoch), offset 555 km s\(^{-1}\) redward of the systemic redshift. From our measurements of collisionally-excited lines of both low- and high-ionization (including [O II]\(\lambda3727\), [Ne III]\(\lambda 3869\) and C III]\(\lambda1909\)) we infer a high ionization parameter (\(\log U\sim -2\)). We detect the rarely-seen N IV]\(\lambda1486\) and N III]\(\lambda1748\) lines in both our low and medium resolution spectra, with other high ionization lines seen in the low resolution spectrum such as He II (blended with O III]) and C IV (with a possible P-Cygni profile). Based on the observed rest-UV line ratios, we cannot conclusively rule out photoionization from AGN, although the high C III]/He II and N III]/He II ratios are compatible with a star-formation explanation. If the observed emission lines are powered by star formation, then the strong N III]\(\lambda1748\) observed may imply an unusually high \(N/O\) abundance. Balmer emission lines (H\(\gamma\), H\(\delta\)) are also detected, and if powered by star formation rather than an AGN we infer a star formation rate of \(\sim 20-30 M_{\odot} yr^{-1}\) (depending on the IMF) and low dust attenuation. Our NIRSpec spectroscopy confirms that GN-z11 is a remarkable galaxy with extreme properties seen 430 Myr after the Big Bang.