Speaker
Description
Stephan’s Quintet (SQ) is a local compact galaxy group system (D = 94 Mpc) that exhibits significant star formation activity. A history of tidal interactions between its five member galaxies and a recent collision between two of them are associated with active star formation, particularly in many shocked regions in the intra-group medium. Using a star cluster candidate (SCC) catalog constructed from HST UV/optical images, we integrate flux measurements from five near-infrared filters (F090W, F150W, F200W, F277W, F356W) obtained from JWST NIRCam observations in 2022. Leveraging the extended photometric baseline from HST and JWST, spanning $\sim$300 nm to $\sim$3500 nm, we perform SED fitting using the CIGALE code to derive key physical properties of the clusters.
The SED fits provide reliable estimates of age, mass, and extinction for the SCCs, enabling us to analyze the variation of their properties across the region.
We find that very young SCCs ($\sim$a few Myr) are predominantly located along previously identified shock regions near the merging galaxies, while older globular clusters are more widely distributed. Our analysis highlights the critical role of NIR photometry in breaking the age-extinction degeneracy. Many SCCs initially assigned older ages based on SED fitting with only HST photometry are reclassified as young, moderately dust-extincted clusters when JWST photometry is included. Additionally, we find a strong spatial correlation between young clusters and cold molecular gas traced by CO emission maps, while also identifying several regions where active star formation persists despite the apparent absence of cold gas. Finally, we explore the potential link between the formation of clusters and past interactions within the compact group, using cluster age estimates to infer the timescales of these events.