Abstract

Contributed Talk - Splinter StarClusters

Tuesday, 08 September 2026, 16:15   (MW-2050)

Near Infrared Wolf–Rayet Features as Tracers of Embedded Young Stellar Clusters

Iker MIllan Irigoyen
Max Planck institute for Astrophysics

Wolf–Rayet (WR) stars represent the final evolutionary stage of massive stars with initial masses of approximately 20–80 M☉. They are characterized by intense stellar winds that produce prominent high-ionization emission lines, such as He II λ4686 Å, N V λ4650Å , and C IV λλ5801,5812Å. In unresolved stellar clusters, the combination of these emission lines gives rise to the broad spectral features known as WR bumps. There are two WR bumps in the optical: the blue (~4610-4710 Å ) and the red (~5750-5850 Å ). This distinctive spectral signatures and their short lifetimes (<10 Myr), make WR stars excellent tracers of young stellar populations. However, some star forming regions are still embedded in their clouds, where the extinction is typically high (Av~ 2.0 mag), making the detection of optical WR features challenging. Near infrared (NIR) observations are less affected by dust extinction, providing an alternative way of studying young stellar populations in these highly obscured environments. We present the first detection of NIR WR features in four embedded young stellar clusters located in a circumnuclear star forming ring. Our analysis combines Integral Field Spectroscopy obtained with MEGARA on the GTC, MUSE on the VLT, and NIRSpec on JWST. We derived the stellar masses, ages and metallicities of the young stellar populations by modelling both the blue and the NIR WR bumps using the HR-pyPopStar stellar population synthesis models. All four regions are characterized by very young ages (~3 Myr) and approximately solar metallicity, demonstrating the potential of this method for identifying and characterizing embedded stellar clusters in highly obscured environments.