TY - JOUR
T1 - JWST NIRCam + NIRSpec
T2 - Interstellar medium and stellar populations of young galaxies with rising star formation and evolving gas reservoirs
AU - Tacchella, Sandro
AU - Johnson, Benjamin D.
AU - Robertson, Brant E.
AU - Carniani, Stefano
AU - D'Eugenio, Francesco
AU - Kumari, Nimisha
AU - Maiolino, Roberto
AU - Nelson, Erica J.
AU - Suess, Katherine A.
AU - Übler, Hannah
AU - Williams, Christina C.
AU - Adebusola, Alabi
AU - Alberts, Stacey
AU - Arribas, Santiago
AU - Bhatawdekar, Rachana
AU - Bonaventura, Nina
AU - Bowler, Rebecca A.A.
AU - Bunker, Andrew J.
AU - Cameron, Alex J.
AU - Curti, Mirko
AU - Egami, Eiichi
AU - Eisenstein, Daniel J.
AU - Frye, Brenda
AU - Hainline, Kevin
AU - Helton, Jakob M.
AU - Ji, Zhiyuan
AU - Looser, Tobias J.
AU - Lyu, Jianwei
AU - Perna, Michele
AU - Rawle, Timothy
AU - Rieke, George
AU - Rieke, Marcia
AU - Saxena, Aayush
AU - Sandles, Lester
AU - Shivaei, Irene
AU - Simmonds, Charlotte
AU - Sun, Fengwu
AU - Willmer, Christopher N.A.
AU - Willott, Chris J.
AU - Witstok, Joris
N1 - Publisher Copyright:
© 2023 Oxford University Press. All rights reserved.
PY - 2023/7/1
Y1 - 2023/7/1
N2 - We present an interstellar medium and stellar population analysis of three spectroscopically confirmed z > 7 galaxies in the Early Release Observations JWST/NIRCam and JWST/NIRSpec data of the SMACS J0723.3-7327 cluster. We use the Bayesian spectral energy distribution-fitting code 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∗~108M⊙) 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 (Zgas= 0.06 Z⊙) has a steeply rising SFH, is very compact (<0.2 kpc), and has a high star formation rate surface density (ΣSFR≈ 22 M⊙yr-1kpc-2), consistent with rapid gas accretion. The two other objects with higher gas-phase metallicities show more complex multicomponent morphologies on kpc scales, indicating that their recent increase in star formation rate is driven by mergers or internal, gravitational instabilities. We discuss effects of assuming different SFH priors or only fitting the photometric data. Our analysis highlights the strength and importance of combining JWST imaging and spectroscopy for fully assessing the nature of galaxies at the earliest epochs.
AB - We present an interstellar medium and stellar population analysis of three spectroscopically confirmed z > 7 galaxies in the Early Release Observations JWST/NIRCam and JWST/NIRSpec data of the SMACS J0723.3-7327 cluster. We use the Bayesian spectral energy distribution-fitting code 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∗~108M⊙) 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 (Zgas= 0.06 Z⊙) has a steeply rising SFH, is very compact (<0.2 kpc), and has a high star formation rate surface density (ΣSFR≈ 22 M⊙yr-1kpc-2), consistent with rapid gas accretion. The two other objects with higher gas-phase metallicities show more complex multicomponent morphologies on kpc scales, indicating that their recent increase in star formation rate is driven by mergers or internal, gravitational instabilities. We discuss effects of assuming different SFH priors or only fitting the photometric data. Our analysis highlights the strength and importance of combining JWST imaging and spectroscopy for fully assessing the nature of galaxies at the earliest epochs.
KW - early Universe
KW - galaxies: evolution
KW - galaxies: formation
KW - galaxies: high-redshift
KW - galaxies: star formation
UR - http://www.scopus.com/inward/record.url?scp=85161501950&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85161501950&partnerID=8YFLogxK
U2 - 10.1093/mnras/stad1408
DO - 10.1093/mnras/stad1408
M3 - Article
AN - SCOPUS:85161501950
SN - 0035-8711
VL - 522
SP - 6236
EP - 6249
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -