The fraction of clumpy star-forming galaxies in nearby galaxies from CLAUDS and HSC-SSP

@misc{popp2026fraction,
  title = {{The fraction of clumpy star-forming galaxies in nearby galaxies from CLAUDS and HSC-SSP}},
  author = {Jürgen J. Popp and Hugh Dickinson and Stephen Serjeant and Lucy F. Fortson and Tobias Géron and Vihang Mehta},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.01152},
  eprint = {2609.01152},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.01152},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - The fraction of clumpy star-forming galaxies in nearby galaxies from CLAUDS and HSC-SSP
AU  - Jürgen J. Popp
AU  - Hugh Dickinson
AU  - Stephen Serjeant
AU  - Lucy F. Fortson
AU  - Tobias Géron
AU  - Vihang Mehta
PY  - 2026
DA  - 2026/09/01
PB  - arXiv
DO  - 10.48550/arxiv.2609.01152
UR  - https://arxiv.org/abs/2609.01152
AB  - Massive, star-forming clumps are regions of intensive star-formation that are commonly observed in high-redshift (z > 1) galaxies. Observations of low-redshift clumpy galaxy analogues are rare but the availability of wide-field galaxy survey data makes the detection of large clumpy galaxy samples much more feasible. We present a population of 12,790 star-forming clumps detected in a mass-complete sample of 5,395 star-forming galaxies (SFGs) at redshifts z≤0.32, located in the XMM-LSS, E-COSMOS and DEEP2-3 fields observed by the Hyper Suprime-Cam Subaru Strategic Survey (HSC-SSP) and CFHT Large Area U-band Deep Survey (CLAUDS). The clumps were detected using an improved version of our Deep Learning (DL)-based object detection framework which uses the ZOOBOT foundation DL-model as a 'backbone' feature extractor. We determined the fraction of star-forming galaxies hosting at least one off-centre clump (f_clumpy) based on a clump definition that requires a clump-galaxy flux ratio in the CLAUDS u-band of ≥8%. We estimate f_clumpy to decrease from ∼31\% at z∼0.3 to ∼23\% at z ∼ 0.1, which aligns well with a low-redshift extrapolation of the clumpy fraction that is measured using high-redshift observations. At fixed redshift, f_clumpy is negatively correlated with the stellar mass and positively correlated with the specific star-formation rate (sSFR) of the host galaxies. When the clump definition is changed to include only clumps with a stellar mass of M_cl ≥ 10^7 M_⊙, we observe a highly increased clumpy fraction of ∼60\% that tends to increase with the stellar mass of the host galaxies but does not show a dependence on the sSFR of the host galaxies.
ER  -