Physical properties of star-forming clumps in nearby galaxies from CLAUDS and HSC-SSP

@misc{popp2026physical,
  title = {{Physical properties of star-forming clumps in nearby galaxies from CLAUDS and HSC-SSP}},
  author = {Jürgen J. Popp and Hugh Dickinson and Stephen Serjeant and Lucy F. Fortson and Vihang Mehta},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.20079},
  eprint = {2609.20079},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.20079},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Physical properties of star-forming clumps in nearby galaxies from CLAUDS and HSC-SSP
AU  - Jürgen J. Popp
AU  - Hugh Dickinson
AU  - Stephen Serjeant
AU  - Lucy F. Fortson
AU  - Vihang Mehta
PY  - 2026
DA  - 2026/09/17
PB  - arXiv
DO  - 10.48550/arxiv.2609.20079
UR  - https://arxiv.org/abs/2609.20079
AB  - Giant Star-forming Clumps (GSFCs) are kpc-scale regions of enhanced star-formation with stellar masses of 10^6 to 10^10 M_⊙ that are commonly observed in high-redshift (z ≳ 1) galaxies but their formation and role in galaxy evolution remain unclear. We applied a Faster R-CNN object detection framework (FRCNN) to identify star-forming clumps in astrophysical imaging data from a mass-complete sample of ∼210,000 low-redshift galaxies (z≲0.32), located in the HSC-SSP Wide and Deep fields observed by the Hyper Suprime-Cam Subaru Strategic Survey (HSC-SSP) and CFHT Large Area U-band Deep Survey (CLAUDS). We present a population of ∼710,000 detected clumps for which we measured the (u)grizy-photometry and derived the physical properties (stellar mass, age, dust extinction and star-formation rate) for each clump by fitting the photometric data to stellar population models. We estimate that the clump Stellar Mass Function (cSMF) for young clumps (<100 Myr) follows a power law with an exponent of α=1.98±0.02 down to a completeness limit of ∼10^8 M_⊙ which is consistent with an in situ formation through violent disk instabilities (VDI). The clumps show elevated star-formation rates and negative gradients in their ages and stellar masses as a function of galactocentric distance. These gradients are steeper than those measured for the intra-clump regions of the host galaxies and are robust against uncertainties introduced by different modelling assumptions. For nearby galaxies we argue that the observed low-redshift clumps are likely analogues of high-redshift GSFCs and that the inward migration of star-forming clumps directly contributes to the central bulge formation of the host galaxy.
ER  -