Year: 2024
Type: article
Abstract: We present Balmer decrement, Hα/Hβ, measurements for a sample of 51 galaxies at redshifts z = 4 − 7 observed with the JWST/NIRSpec micro-shutter assembly (MSA), as part of the JWST Advanced Deep Extragalactic Survey (JADES). Leveraging 28-hour long exposures and the efficiency of the prism/clear configuration (but also using information from the medium-resolution gratings), we were able to directly probe the low-mass end of the galaxy population, reaching stellar masses, M⋆, as low as 107 M⊙. We find that the correlation between the Balmer decrement and M⋆ is already established at these high redshifts, indicating a rapid buildup of dust in moderately massive galaxies at such early epochs. The lowest-mass galaxies in our sample (M⋆ = 1 − 3 × 107 M⊙) display a remarkably low Balmer decrement of 2.88 ± 0.08, consistent with Case B, suggesting very little dust content. However, we warn that such a low observed Balmer decrement may also partly be a consequence of an intrinsically lower Hα/Hβ resulting from the extreme conditions of the ionised gas in these primeval and unevolved systems. We further compare the Balmer decrement to continuum-derived star formation rates (SFRs), finding tentative evidence of a correlation, which likely traces the underlying connection between the SFR and the mass of cold gas. However, we note that larger samples are required to distinguish between direct and primary correlations from indirect and secondary dependences at such high redshifts.
Authors: Lester Sandles, Francesco D’Eugenio, Roberto Maiolino, Tobias J. Looser, Santiago Arribas, William M. Baker, Nina Bonaventura, Andrew J. Bunker, Alex J. Cameron, Stefano Carniani, Stephane Charlot, Jacopo Chevallard, Mirko Curti, Emma Curtis-Lake, Anna de Graaff, Daniel J. Eisenstein, Kevin Hainline, Zhiyuan Ji, Benjamin D. Johnson, Gareth C. Jones, Nimisha Kumari, Erica Nelson, Michele Perna, Tim Rawle, Hans-Walter Rix, Brant Robertson, Bruno Rodríguez Del Pino, Jan Scholtz, Irene Shivaei, Renske Smit, Fengwu Sun, Sandro Tacchella, Hannah Übler, Christina C. Williams, Chris Willott, Joris Witstok
Institutions: University of Cambridge, Centro de Astrobiología, University of Oxford, Scuola Normale Superiore, Centre National de la Recherche Scientifique, Institut d'Astrophysique de Paris, Sorbonne Université, University of Hertfordshire, Max Planck Institute for Astronomy, Center for Astrophysics Harvard & Smithsonian, University of Arizona, Space Telescope Science Institute, University of Colorado Boulder, European Space Agency, European Space Astronomy Centre, University of California, Santa Cruz, Liverpool John Moores University, NSF NOIRLab, Herzberg Institute of Astrophysics
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1175115578, G1325949514, G1577046871, G1855990336, G2021250021, G2144673021, G2262748287, G2309174360, Star formation in galaxies from the Epoch of Reionisation to the present day with JWST, G2601397997, G2660406951, G300979063, G3228396264, G3275705967, G3452655474, G3480869486, G3660973570, G3681454997, G4042783231, G425668148, G430777504, G434337789, G4501905872, G4915654406, G5080475149, G5195188938, G531848386, G5368796297, G5421974903, G6307073466, G7084143925, G7736885172, Dissecting galaxies at the cosmic dawn, G8931419319, G971458805, G99296377
OpenAlex ID: W6903374268
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