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Main Authors: Liang, Yuan, Li, Guang-Wei, Tsai, Chao-Wei, Wu, Jingwen
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2509.03153
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author Liang, Yuan
Li, Guang-Wei
Tsai, Chao-Wei
Wu, Jingwen
author_facet Liang, Yuan
Li, Guang-Wei
Tsai, Chao-Wei
Wu, Jingwen
contents We present a new catalogue of 578 OB cluster (OBC) candidates in the Andromeda galaxy (M31), identified using a MeanShift-based algorithm on HST's F275W-band imaging from the PHAT (Dalcanton et al. 2012) and PHAST (Chen et al. 2025) Hubble surveys. These clusters exhibit typical half-light radii of 1-2 pc and strong ultraviolet luminosities indicative of recent massive star formation. Spatial analysis reveals a pronounced north-south asymmetry: clusters in the northern disc show tight associations with giant molecular clouds (GMCs), while southern clusters appear more compact and luminous but less correlated with molecular gas. Two-point correlation functions demonstrate significant clustering of OBC candidates on scales 100 pc and a strong spatial association with GMCs, consistent with hierarchical star formation in dense gas-rich environments. These findings offer new constraints on the early evolution and feedback-driven dispersal of young stellar clusters across galactic discs.
format Preprint
id arxiv_https___arxiv_org_abs_2509_03153
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A comprehensive catalogue of OB cluster candidates in M31 and their association with giant molecular clouds
Liang, Yuan
Li, Guang-Wei
Tsai, Chao-Wei
Wu, Jingwen
Astrophysics of Galaxies
We present a new catalogue of 578 OB cluster (OBC) candidates in the Andromeda galaxy (M31), identified using a MeanShift-based algorithm on HST's F275W-band imaging from the PHAT (Dalcanton et al. 2012) and PHAST (Chen et al. 2025) Hubble surveys. These clusters exhibit typical half-light radii of 1-2 pc and strong ultraviolet luminosities indicative of recent massive star formation. Spatial analysis reveals a pronounced north-south asymmetry: clusters in the northern disc show tight associations with giant molecular clouds (GMCs), while southern clusters appear more compact and luminous but less correlated with molecular gas. Two-point correlation functions demonstrate significant clustering of OBC candidates on scales 100 pc and a strong spatial association with GMCs, consistent with hierarchical star formation in dense gas-rich environments. These findings offer new constraints on the early evolution and feedback-driven dispersal of young stellar clusters across galactic discs.
title A comprehensive catalogue of OB cluster candidates in M31 and their association with giant molecular clouds
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2509.03153