Speaker: Kelsey Johnson
Speaker's Institution: Virginia
Seminar Title:Ancient Relics & Infant Titans: Probing Massive Star Cluster Formation with ALMA
Abstract:
Observationally constraining the physical conditions that gave rise to ancient globular star
clusters has been a long-standing challenge, yet we know these extreme objects were formed
prolifically in the early universe. Now with the ALMA Observatory on-line, we can begin to
probe the birth environments of analogous massive clusters in a variety of "local" galaxies with
sufficient angular resolution. I will give an overview of ALMA observations of galaxies in
which candidate proto-super star cluster molecular clouds have been identified. These new data
probe the physical conditions that give rise to super star clusters, providing information on their
densities, pressures, and temperatures. In particular, the observations indicate that these clouds
may be subject to external pressures of P/k > 10^8 K cm^{-3}, which is consistent with the
prevalence of optically observed adolescent super star clusters in interacting galaxy systems and
other high pressure environments. ALMA observations also enable an assessement of the
molecular cloud chemical abundances in the regions surrounding super star clusters. Molecular
clouds associated with existing super star clusters are strongly correlated with HCO+ emission,
but appear to have relatively low ratio of CO/HCO+ emission compared to other clouds,
indicating that the super star clusters are impacting the molecular abundances in their vicinity.

Location:	Room 1400 Biomedical and Physical Sciences Building [map]
Price:	free
Sponsor:	Biomedical and Physical Sciences Building
Contact:	Shawna Prater prater@pa.msu.edu
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