The clumpy fraction of galaxies at z=1−9 with JADES: evidence for a mass-dependent transition in clump origin

@misc{puskas2026clumpy,
  title = {{The clumpy fraction of galaxies at $z=1-9$ with JADES: evidence for a mass-dependent transition in clump origin}},
  author = {Dávid Puskás and Sandro Tacchella and Phoebe Chapman and Floor van Donkelaar and Andrew J. Bunker and Courtney Carreira and A. Lola Danhaive and Francesco D'Eugenio and Qiao Duan and Patricia Iglesias-Navarro and Amanda Stoffers and Hannah Übler and Yongda Zhu and Mirko Curti and Emma Curtis-Lake and Kevin Hainline and Eiichi Egami and Daniel J. Eisenstein and Zhiyuan Ji and Benjamin D. Johnson and Roberto Maiolino and Marcia Rieke and Brant Robertson and Christina C. Williams},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.28515},
  eprint = {2610.28515},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.28515},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - The clumpy fraction of galaxies at z=1−9 with JADES: evidence for a mass-dependent transition in clump origin
AU  - Dávid Puskás
AU  - Sandro Tacchella
AU  - Phoebe Chapman
AU  - Floor van Donkelaar
AU  - Andrew J. Bunker
AU  - Courtney Carreira
AU  - A. Lola Danhaive
AU  - Francesco D'Eugenio
AU  - Qiao Duan
AU  - Patricia Iglesias-Navarro
AU  - Amanda Stoffers
AU  - Hannah Übler
AU  - Yongda Zhu
AU  - Mirko Curti
AU  - Emma Curtis-Lake
AU  - Kevin Hainline
AU  - Eiichi Egami
AU  - Daniel J. Eisenstein
AU  - Zhiyuan Ji
AU  - Benjamin D. Johnson
AU  - Roberto Maiolino
AU  - Marcia Rieke
AU  - Brant Robertson
AU  - Christina C. Williams
PY  - 2026
DA  - 2026/10/20
PB  - arXiv
DO  - 10.48550/arxiv.2610.28515
UR  - https://arxiv.org/abs/2610.28515
AB  - We measure the fraction of clumpy galaxies (f_clumpy) over the redshift range z=1−9 and stellar masses log_10(M_⋆/M_⊙) ≥ 8 using JWST/NIRCam imaging from JADES. We define clumps as compact off-centre surface-brightness peaks with characteristic sizes of a few hundred parsecs, and develop a dendrogram-based clump-finding method with astrodendro to identify them directly in rest-frame UV, blue, and optical images. Clump-detection completeness is quantified through injection-recovery simulations, which we use to define (M_⋆, z)-dependent 50 per cent completeness-limited f_clumpy, alongside a probability-weighted completeness-corrected statistic for comparison. For the full sample, the blue and optical f_clumpy reach ≈55 per cent at z≈1−2 and decline to ≲5 per cent by z≈8−9, while the UV fraction remains higher at ≈12 per cent. At z≈1−2, f_clumpy increases strongly with stellar mass, from ≈35 per cent in the lowest-mass bin to ≈85 per cent at log_10(M_⋆/M_⊙)≥10. Most clumpy galaxies host only one or two robustly detected off-centre clumps, while higher-multiplicity systems occur preferentially in massive, strongly star-forming galaxies at low to intermediate redshift. Comparison with major merger rates suggests that mergers could account for a substantial fraction of low-mass (log_10(M_⋆/M_⊙)<8.5), high-redshift clumpy galaxies, while the observed fractions in more massive systems (log_10(M_⋆/M_⊙)>9) require an additional in situ clump-formation channel. Our results are consistent with a transition from merger-dominated clumpy morphologies at early times and low stellar masses to an increasing contribution from in situ clump-formation channels, such as disc instabilities, in more massive systems.
ER  -