Temporarily Quiescent Galaxies at Cosmic Dawn: Probing Bursty Star Formation

The bursty, time-variable nature of star formation in the first billion years, as revealed by JWST, drives phases of temporary quiescence in low-mass galaxies that quench after starbursts. These galaxies provide unique probes of the burstiness of early star formation and its underlying physical proc...

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Main Authors: Viola Gelli, Andrea Pallottini, Stefania Salvadori, Andrea Ferrara, Charlotte Mason, Stefano Carniani, Michele Ginolfi
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/adc722
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author Viola Gelli
Andrea Pallottini
Stefania Salvadori
Andrea Ferrara
Charlotte Mason
Stefano Carniani
Michele Ginolfi
author_facet Viola Gelli
Andrea Pallottini
Stefania Salvadori
Andrea Ferrara
Charlotte Mason
Stefano Carniani
Michele Ginolfi
author_sort Viola Gelli
collection DOAJ
description The bursty, time-variable nature of star formation in the first billion years, as revealed by JWST, drives phases of temporary quiescence in low-mass galaxies that quench after starbursts. These galaxies provide unique probes of the burstiness of early star formation and its underlying physical processes. Using the serra cosmological zoom-in simulations, we analyze over 200 galaxies with M _⋆ < 10 ^9.5 M _⊙ at z ∼ 6–8, finding that most experience quiescent phases driven by stellar feedback, with minimal influence from environmental effects. The fraction of temporarily quiescent galaxies increases with decreasing mass and luminosity, representing the dominant population at M _⋆ < 10 ^8 M _⊙ and M _UV > −17. By forward modeling their spectral energy distributions, we show that they are faint (〈 M _UV 〉 = −15.6 for M _⋆ = 10 ^8 M _⊙ ), have strong Balmer breaks (>0.5), and no emission lines. Comparing our predicted fractions with JWST results, we find similar luminosity-dependent trends; however, the observed fractions of temporarily quiescent galaxies at M _UV ∼ −20 to −19 are higher, suggesting that stronger feedback or additional mechanisms beyond supernovae may be at play. We propose searching for F200W dropouts and satellites in the proximity (<5″) of massive (>10 ^10 M _⊙ ) galaxies as effective strategies to uncover the hidden majority of faint ( M _UV > −17), temporarily quiescent systems, crucial for constraining early feedback processes in low-mass galaxies.
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spelling doaj-art-eabce9eb316f4245a7ff669a02c3cb4d2025-08-20T03:53:47ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01985112610.3847/1538-4357/adc722Temporarily Quiescent Galaxies at Cosmic Dawn: Probing Bursty Star FormationViola Gelli0https://orcid.org/0000-0001-5487-0392Andrea Pallottini1https://orcid.org/0000-0002-7129-5761Stefania Salvadori2https://orcid.org/0000-0001-7298-2478Andrea Ferrara3https://orcid.org/0000-0002-9400-7312Charlotte Mason4https://orcid.org/0000-0002-3407-1785Stefano Carniani5https://orcid.org/0000-0002-6719-380XMichele Ginolfi6https://orcid.org/0000-0002-9122-1700Cosmic Dawn Center (DAWN) , Denmark ; viola.gelli@nbi.ku.dk; Niels Bohr Institute, University of Copenhagen , Jagtvej 128, 2200 København N, DenmarkDipartimento di Fisica “Enrico Fermi,” Universitá di Pisa , Largo Bruno Pontecorvo 3, Pisa I-56127, Italy; Scuola Normale Superiore , Piazza dei Cavalieri 7, I-56126 Pisa, ItalyDipartimento di Fisica e Astronomia, Universitá degli Studi di Firenze , via G. Sansone 1, 50019, Sesto Fiorentino, Italy; INAF/Osservatorio Astrofisico di Arcetri , Largo E. Fermi 5, I-50125, Firenze, ItalyScuola Normale Superiore , Piazza dei Cavalieri 7, I-56126 Pisa, ItalyCosmic Dawn Center (DAWN) , Denmark ; viola.gelli@nbi.ku.dk; Niels Bohr Institute, University of Copenhagen , Jagtvej 128, 2200 København N, DenmarkScuola Normale Superiore , Piazza dei Cavalieri 7, I-56126 Pisa, ItalyDipartimento di Fisica e Astronomia, Universitá degli Studi di Firenze , via G. Sansone 1, 50019, Sesto Fiorentino, Italy; INAF/Osservatorio Astrofisico di Arcetri , Largo E. Fermi 5, I-50125, Firenze, ItalyThe bursty, time-variable nature of star formation in the first billion years, as revealed by JWST, drives phases of temporary quiescence in low-mass galaxies that quench after starbursts. These galaxies provide unique probes of the burstiness of early star formation and its underlying physical processes. Using the serra cosmological zoom-in simulations, we analyze over 200 galaxies with M _⋆ < 10 ^9.5 M _⊙ at z ∼ 6–8, finding that most experience quiescent phases driven by stellar feedback, with minimal influence from environmental effects. The fraction of temporarily quiescent galaxies increases with decreasing mass and luminosity, representing the dominant population at M _⋆ < 10 ^8 M _⊙ and M _UV > −17. By forward modeling their spectral energy distributions, we show that they are faint (〈 M _UV 〉 = −15.6 for M _⋆ = 10 ^8 M _⊙ ), have strong Balmer breaks (>0.5), and no emission lines. Comparing our predicted fractions with JWST results, we find similar luminosity-dependent trends; however, the observed fractions of temporarily quiescent galaxies at M _UV ∼ −20 to −19 are higher, suggesting that stronger feedback or additional mechanisms beyond supernovae may be at play. We propose searching for F200W dropouts and satellites in the proximity (<5″) of massive (>10 ^10 M _⊙ ) galaxies as effective strategies to uncover the hidden majority of faint ( M _UV > −17), temporarily quiescent systems, crucial for constraining early feedback processes in low-mass galaxies.https://doi.org/10.3847/1538-4357/adc722High-redshift galaxiesCosmologyGalaxy evolutionDwarf galaxies
spellingShingle Viola Gelli
Andrea Pallottini
Stefania Salvadori
Andrea Ferrara
Charlotte Mason
Stefano Carniani
Michele Ginolfi
Temporarily Quiescent Galaxies at Cosmic Dawn: Probing Bursty Star Formation
The Astrophysical Journal
High-redshift galaxies
Cosmology
Galaxy evolution
Dwarf galaxies
title Temporarily Quiescent Galaxies at Cosmic Dawn: Probing Bursty Star Formation
title_full Temporarily Quiescent Galaxies at Cosmic Dawn: Probing Bursty Star Formation
title_fullStr Temporarily Quiescent Galaxies at Cosmic Dawn: Probing Bursty Star Formation
title_full_unstemmed Temporarily Quiescent Galaxies at Cosmic Dawn: Probing Bursty Star Formation
title_short Temporarily Quiescent Galaxies at Cosmic Dawn: Probing Bursty Star Formation
title_sort temporarily quiescent galaxies at cosmic dawn probing bursty star formation
topic High-redshift galaxies
Cosmology
Galaxy evolution
Dwarf galaxies
url https://doi.org/10.3847/1538-4357/adc722
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