1. JWST NIRCam + NIRSpec: interstellar medium and stellar populations of young galaxies with rising star formation and evolving gas reservoirs
- Author
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Sandro Tacchella, Benjamin D Johnson, Brant E Robertson, Stefano Carniani, Francesco D’Eugenio, Nimisha Kumari, Roberto Maiolino, Erica J Nelson, Katherine A Suess, Hannah Übler, Christina C Williams, Alabi Adebusola, Stacey Alberts, Santiago Arribas, Rachana Bhatawdekar, Nina Bonaventura, Rebecca A A Bowler, Andrew J Bunker, Alex J Cameron, Mirko Curti, Eiichi Egami, Daniel J Eisenstein, Brenda Frye, Kevin Hainline, Jakob M Helton, Zhiyuan Ji, Tobias J Looser, Jianwei Lyu, Michele Perna, Timothy Rawle, George Rieke, Marcia Rieke, Aayush Saxena, Lester Sandles, Irene Shivaei, Charlotte Simmonds, Fengwu Sun, Christopher N A Willmer, Chris J Willott, and Joris Witstok
- Subjects
Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
We present an interstellar medium and stellar population analysis of three spectroscopically confirmed $z>7$ galaxies in the ERO JWST NIRCam and JWST NIRSpec data of the SMACS J0723.3-7327 cluster. We use the Bayesian spectral energy distribution (SED) fitting code \texttt{Prospector} with a flexible star-formation history (SFH), a variable dust attenuation law, and a self-consistent model of nebular emission (continuum and emission lines). Importantly, we self-consistently fit both the emission line fluxes from JWST NIRSpec and the broad-band photometry from JWST NIRCam, taking into account slit-loss effects. We find that these three $z=7.6-8.5$ galaxies ($M_{\star}\approx10^{8}~M_{\odot}$) are young with rising SFHs and mass-weighted ages of $3-4$ Myr, though we find indications for underlying older stellar populations. The inferred gas-phase metallicities broadly agree with the direct metallicity estimates from the auroral lines. The galaxy with the lowest gas-phase metallicity ($\mathrm{Z}_{\rm gas}=0.06~\mathrm{Z}_{\odot}$) has a steeply rising SFH, is very compact ($, 14 pages, 9 figures; accepted for publication in MNRAS
- Published
- 2023