Feedback Size Measurements Around LMC Cluster-Nebula Systems 57 views

Stellar feedback from young star clusters shapes the structure of the interstellar medium (ISM), but the measured spatial scales of feedback depend on tracer choice, source definition, morphology, and image resolution. We investigate feedback-associated emission around cluster-nebula systems in the Large Magellanic Cloud (LMC) using Hα, 8 μm, and 24 μm observations. We compare a visually selected sample from the Bica catalog with an automatically identified peak-finder (PF) sample, and measure radial intensity profiles using several operational size definitions: the half-maximum radius, second-moment radius, and isophotal radius. We also compare native-resolution measurements with intentionally smoothed images to test how feedback scales would appear in lower-resolution observations of more distant galaxies. We find that Hα and 24 μm radii are broadly correlated for the half-maximum and second-moment definitions, indicating that ionized gas and warm dust generally trace related star-forming structures. However, the isophotal radius gives systematically smaller 24 μm sizes, showing that the inferred tracer relationship depends strongly on the adopted radius definition. The Bica and PF samples are statistically distinct, with the Bica sample preferentially selecting brighter and more extended systems, while the PF sample isolates smaller local emission maxima. Smoothing mainly increases half-maximum radii and decreases peak intensities, while integrated fluxes and isophotal extents are less affected. These results show that feedback-size measurements are shaped by both physical structure and methodology, highlighting the need for consistent source definitions and resolution-aware measurements when comparing feedback across galaxies.

BS (Bachelor of Science)

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2026-05-12