Details

Autor(en) / Beteiligte

• Shapley, Alice E.
• Sanders, Ryan L.
• Reddy, Naveen A.
• Topping, Michael W.
• Brammer, Gabriel B.

Titel

JWST/NIRSpec Balmer-line Measurements of Star Formation and Dust Attenuation at z ∼ 3–6

Ist Teil von

• The Astrophysical journal, 2023-09, Vol.954 (2), p.157

Ort / Verlag

Philadelphia: The American Astronomical Society

Erscheinungsjahr

2023

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Abstract We present an analysis of the star formation rates (SFRs) and dust attenuation properties of star-forming galaxies at 2.7 ≤ z < 6.5 drawn from the Cosmic Evolution Early Release Science Survey. Our analysis is based on JWST/NIRSpec Micro-Shutter Assembly R ∼ 1000 spectroscopic observations covering approximately 1–5 μ m. Our primary rest-frame optical spectroscopic measurements are H α /H β Balmer decrements, which we use as an indicator of nebular dust attenuation. In turn, we use Balmer decrements to obtain dust-corrected H α -based SFRs (i.e., SFR(H α )). We construct the relationship between SFR(H α ) and stellar mass ( M * ) in three bins of redshift (2.7 ≤ z < 4.0, 4.0 ≤ z < 5.0, and 5.0 ≤ z < 6.5), which represents the first time the star-forming main sequence has been traced at these redshifts using direct spectroscopic measurements of Balmer emission as a proxy for SFR. In tracing the relationship between SFR(H α ) and M * back to such early times ( z > 3), it is essential to use a conversion factor between H α and SFR that accounts for the subsolar metallicity prevalent among distant galaxies. We also use measured Balmer decrements to investigate the relationship between dust attenuation and stellar mass out to z ∼ 6. The lack of significant redshift evolution in attenuation at fixed stellar mass, previously confirmed using Balmer decrements out to z ∼ 2.3, appears to hold out to z ∼ 6.5. Given the rapidly evolving gas, dust, and metal content of star-forming galaxies at fixed mass, this lack of significant evolution in attenuation provides an ongoing challenge to explain.