Age and Mass Signatures in the Multiband Second-order Image Structure of Young Star Clusters in M31
Abstract
The ages and masses of star clusters may leave systematic signatures in the second-order spatial structure of semi-resolved photometric images. To test this hypothesis, we analyze the images using the Hessian matrix and identify basic luminous structures, termed peak cores. Applying this analysis to six-band PHAT/AP images of 1249 M31 clusters with CMD-based ages of 10--300 Myr and masses of 102.2--104.5 M⊙, we examine the correlations of age and mass with the peak-core structural parameters, CS and Q. Younger clusters show larger CS values in the ultraviolet bands, with the strongest age--CS anti-correlation in F336W (ρ=−0.61), whereas more massive clusters show smaller Q values, most clearly in F336W (ρ=−0.44). These correlations suggest that the contrast of UV-bright peak cores decreases with age, whereas increasing mass alters the abundance and spatial organization of detectable structures across different bands.
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BibTeX
@misc{liang2026mass,
title = {{Age and Mass Signatures in the Multiband Second-order Image Structure of Young Star Clusters in M31}},
author = {Yuan Liang and Chao-Wei Tsai and Jingwen Wu},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.23741},
eprint = {2609.23741},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.23741},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Age and Mass Signatures in the Multiband Second-order Image Structure of Young Star Clusters in M31
AU - Yuan Liang
AU - Chao-Wei Tsai
AU - Jingwen Wu
PY - 2026
DA - 2026/09/20
PB - arXiv
DO - 10.48550/arxiv.2609.23741
UR - https://arxiv.org/abs/2609.23741
AB - The ages and masses of star clusters may leave systematic signatures in the second-order spatial structure of semi-resolved photometric images. To test this hypothesis, we analyze the images using the Hessian matrix and identify basic luminous structures, termed peak cores. Applying this analysis to six-band PHAT/AP images of 1249 M31 clusters with CMD-based ages of 10--300 Myr and masses of 10^2.2--10^4.5 M_⊙, we examine the correlations of age and mass with the peak-core structural parameters, C_S and Q. Younger clusters show larger C_S values in the ultraviolet bands, with the strongest age--C_S anti-correlation in F336W (ρ=−0.61), whereas more massive clusters show smaller Q values, most clearly in F336W (ρ=−0.44). These correlations suggest that the contrast of UV-bright peak cores decreases with age, whereas increasing mass alters the abundance and spatial organization of detectable structures across different bands.
ER -