SCALES. II. The Internal Composition of Giant Star-Forming Clumps at z = 1 − 4

@misc{kalita2026scales,
  title = {{SCALES. II. The Internal Composition of Giant Star-Forming Clumps at $z = 1 - 4$}},
  author = {Boris S. Kalita and Adélaïde Claeyssens and Luis C. Ho and Miroslava Dessauges-Zavadsky and Natascha M. Förster Schreiber and Emanuele Daddi and John D. Silverman and Naval Kishor Bhadari and Changhao Chen and Fangzhou Jiang and Ke Wang and Jinning Liang and Alvaro Segovia Otero and Jinyi Shangguan},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.03867},
  eprint = {2610.03867},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.03867},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - SCALES. II. The Internal Composition of Giant Star-Forming Clumps at z = 1 − 4
AU  - Boris S. Kalita
AU  - Adélaïde Claeyssens
AU  - Luis C. Ho
AU  - Miroslava Dessauges-Zavadsky
AU  - Natascha M. Förster Schreiber
AU  - Emanuele Daddi
AU  - John D. Silverman
AU  - Naval Kishor Bhadari
AU  - Changhao Chen
AU  - Fangzhou Jiang
AU  - Ke Wang
AU  - Jinning Liang
AU  - Alvaro Segovia Otero
AU  - Jinyi Shangguan
PY  - 2026
DA  - 2026/10/29
PB  - arXiv
DO  - 10.48550/arxiv.2610.03867
UR  - https://arxiv.org/abs/2610.03867
AB  - Star-forming structures of scale ∼0.5−1 kpc, dubbed 'giant' clumps, are routinely detected in unlensed surveys of z > 1 galaxies. Explaining them requires characterizing their internal structure. In this work, part of the Star-Forming Clumps As Layered Emergent Structures (SCALES) series, we hence ask: What is inside a giant clump? We analyze 23 lensed galaxies at z=1−4 with JWST/NIRCam using a difference-of-Gaussian decomposition to model (lensed) clumps at ≈ 50−400 pc scales, and the surrounding extended component (EC) at giant clump scales. Associating clumps to ECs, we identify 72 giant clumps. We find the constituent clumps above our mass completeness limit (10^7.1 M_⊙) in a giant clump to be consistent with random sampling of the clump stellar mass function (CSMF), hence holding no information about their host. This agrees qualitatively with both prevailing scenarios for giant clumps: (I) long-lived structures with constantly renewed constituents, and (II) blended random clump associations. As most models lack predictions for their internal mass distribution, our observations provide an empirical constraint. Finally, the CSMF follows a power law of slope 1.88±0.04 above a break at ∼10^7.5 M_⊙, close to our completeness limit. The giant clumps follow a consistent slope (1.95±0.15), giving the same scale-free mass function slope at (lensed) clump and giant clump scales. Within giant clumps, both the EC mass, if made up of undetected clumps, and the mass share of the most massive clump are consistent with the CSMF slope continuing down to ≈10^5.5−10^6 M_⊙, while the latter rejects an extension below 10^5 M_⊙.
ER  -