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

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

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

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 μm. Our primary rest-frame optical spectroscopic measurements are Hα/Hβ Balmer decrements, which we use as an indicator of nebular dust attenuation. In turn, we use Balmer decrements to obtain dust-corrected Hα-based SFRs (i.e., SFR(Hα)). We construct the relationship between SFR(Hα) 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(Hα) and M * back to such early times (z > 3), it is essential to use a conversion factor between Hα 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.

Original languageEnglish
Article number157
JournalAstrophysical Journal
Volume954
Issue number2
DOIs
StatePublished - Sep 1 2023

Bibliographical note

Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.

Funding

We acknowledge the entire CEERS team for their effort to design and execute this Early Release Science observational program, especially the work to design the MSA observations. This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-03127 for JWST. The specific observations analyzed can be accessed via doi:10.17909/z7p0-8481. We also acknowledge support from NASA grant JWST-GO-01914. Support for this work was also provided through the NASA Hubble Fellowship grant #HST-HF2-51469.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. We acknowledge the entire CEERS team for their effort to design and execute this Early Release Science observational program, especially the work to design the MSA observations. This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-03127 for JWST. The specific observations analyzed can be accessed via doi: 10.17909/z7p0-8481 . We also acknowledge support from NASA grant JWST-GO-01914. Support for this work was also provided through the NASA Hubble Fellowship grant #HST-HF2-51469.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.

FundersFunder number
National Aeronautics and Space Administration#HST-HF2-51469.001-A, JWST-GO-01914
National Aeronautics and Space Administration
Entomological Society of America
Space Telescope Science InstituteNAS5-26555
Space Telescope Science Institute
Canadian Space AgencyNAS5-03127
Canadian Space Agency

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

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