Stellar Bars Reshape the Spatial Distribution of UV-bright Clumps in Nearby Galaxies
Abstract
Stellar bars redistribute gas and angular momentum in disk galaxies, but whether they mainly change the amount or the spatial organization of recent star formation remains uncertain. We use archival HST/WFC3 F275W imaging to study 70 barred galaxies and 95 unbarred control galaxies matched in stellar mass, optical color, redshift, and F275W background noise. A uniform dendrogram-based procedure identifies 95,486 UV-bright star-forming clumps. We compare their radial and azimuthal distributions, central F275W emission, and luminosity and size distribution functions. Relative to their controls, barred galaxies show a deficit of clumps at intermediate radii broadly corresponding to the bar region, followed by a local recovery near the bar ends. Their clumps are also preferentially concentrated along the bar major axis. These spatial differences are stronger in high-mass galaxies. Normalized bar length is more closely associated with the radial redistribution and central F275W concentration than bar ellipticity, although its relation to the azimuthal distribution is less uniform. When galactocentric radius is normalized by bar length, the recovery occurs near R/Rbar∼1, indicating that the bar sets a characteristic scale for the redistribution. Despite these spatial differences, barred and control galaxies have broadly similar clump luminosity and size distribution functions. Our results suggest that stellar bars mainly reorganize where recent star formation occurs, rather than substantially altering the observed luminosities and sizes of individual UV clumps, and that this effect depends on galaxy mass and bar extent.
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BibTeX
@misc{zhou2026stellar,
title = {{Stellar Bars Reshape the Spatial Distribution of UV-bright Clumps in Nearby Galaxies}},
author = {Zhimin Zhou and Jianfei Liu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.41355},
eprint = {2610.41355},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.41355},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Stellar Bars Reshape the Spatial Distribution of UV-bright Clumps in Nearby Galaxies
AU - Zhimin Zhou
AU - Jianfei Liu
PY - 2026
DA - 2026/10/30
PB - arXiv
DO - 10.48550/arxiv.2610.41355
UR - https://arxiv.org/abs/2610.41355
AB - Stellar bars redistribute gas and angular momentum in disk galaxies, but whether they mainly change the amount or the spatial organization of recent star formation remains uncertain. We use archival HST/WFC3 F275W imaging to study 70 barred galaxies and 95 unbarred control galaxies matched in stellar mass, optical color, redshift, and F275W background noise. A uniform dendrogram-based procedure identifies 95,486 UV-bright star-forming clumps. We compare their radial and azimuthal distributions, central F275W emission, and luminosity and size distribution functions. Relative to their controls, barred galaxies show a deficit of clumps at intermediate radii broadly corresponding to the bar region, followed by a local recovery near the bar ends. Their clumps are also preferentially concentrated along the bar major axis. These spatial differences are stronger in high-mass galaxies. Normalized bar length is more closely associated with the radial redistribution and central F275W concentration than bar ellipticity, although its relation to the azimuthal distribution is less uniform. When galactocentric radius is normalized by bar length, the recovery occurs near R/R_bar∼1, indicating that the bar sets a characteristic scale for the redistribution. Despite these spatial differences, barred and control galaxies have broadly similar clump luminosity and size distribution functions. Our results suggest that stellar bars mainly reorganize where recent star formation occurs, rather than substantially altering the observed luminosities and sizes of individual UV clumps, and that this effect depends on galaxy mass and bar extent.
ER -