A Census of Star Clusters and HII Regions in Extreme Extragalactic Environments

Sean Linden
University of Massachusetts, Amherst
Tuesday, February 16, 2021
2:00 pm
Zoom Seminar


Local luminous infrared galaxies (LIRGs) are the ideal laboratories for studying star formation in the most extreme merger-driven environments; conditions which may be analogous to the star-forming environments of high-redshift galaxies. With HST and the VLA we are able to make fundamental conclusions about the nature of both the obscured and unobscured star formation in these systems. Here, I will discuss my work in identifying and characterizing the UV-bright population of super star clusters (SSCs) for LIRGs in the Great Observatories All-Sky LIRG Survey. A major result of these studies is the discovery that, relative to the normal star-forming galaxies studied in the PHANGS and LEGUS surveys, the survival rate and maximum mass of SSCs is affected by the active merging-environment of LIRGs. Additionally, by imaging the resolved (<1”) 1 – 33 GHz radio continuum emission we have shown that 33 GHz emission from extranuclear star-forming regions in both normal and starburst galaxies is heavily-dominated by thermal free-free radiation, making it one of the most direct and universal probes of the ionizing photon production rate from massive star-forming regions. Finally, I will discuss ongoing effort within the Clusters, Clumps, Dust, and Gas (CCDG) survey to establish the relationship between the stellar and nebular extinction for the most extreme SSCs in LIRGs, and to search for SSCs in the NIR which are completely obscured in the UV. Future JWST observations of LIRGs in the NIR-MIR will allow us to identify the very youngest (1-3 Myr), and most highly-embedded (Av > 50) SSCs, which likely power the bulk of the current SFR in these extreme systems.


Vivian U