Young star clusters in the act of emerging: a JWST view of stellar feedback and timescales

by Alex Pedrini (Stockholm University)

Wednesday 13 May 2026, 13:30 → 14:30 Europe/Stockholm

FC61 (AlbaNova Main Building)

Young star clusters form embedded in dusty gas clouds, with feedback from massive stars driving their emergence over a few million years. The infrared capabilities of the JWST now allow us to capture this process in unprecedented detail, enabling the detection and characterisation of thousands of emerging young star clusters (eYSCs) at few-parsec scales in nearby galaxies.

While high-resolution studies in the Milky Way provide detailed insight into individual regions, examining the full population of clusters in nearby galaxies is essential to understand the broader effects of star formation across diverse galactic environments.

In this seminar, I will present the main results of my PhD project, which focus on the emergence phase of star clusters as a probe of feedback timescales. I will introduce the census of eYSCs identified in the FEAST (Feedback in Emerging extrAgalactic Star ClusTer) sample, including M51, M83, NGC 628, and the low-metallicity dwarf NGC 4449. I will show that these clusters exhibit distinct near-infrared colours, driven by hot dust and polycyclic aromatic hydrocarbon (PAH) emission at 3.3 μm, and are largely absent from UV–optical HST-selected cluster samples.

I will discuss the challenges of modelling their spectral energy distributions with current tools, and present observational evidence for a relation between cluster emerging timescales and stellar mass. Finally, I will highlight the power of such studies to investigate the morphologies of different ISM gas phases in star-forming regions and their relation to the powering stellar sources, providing new constraints on the role of stellar feedback in shaping their evolution.