Speaker
Kathryn Grasha
(University of Massachusetts)
Description
A turbulent interstellar medium will drive the hierarchical nature of star formation, resulting in a
smoothly varying distribution of substructure, where bound star clusters occupy the smallest,
densest regions. We use young stellar clusters to trace the unbound hierarchical star-forming
structures for several nearby galaxies drawn from the Legacy ExtraGalactic UV Survey (LEGUS).
We implement the angular two point correlation function to quantify the clustering among stellar
clusters as a function of spatial scale and age to establish whether the clustering strength and the
survival timescale of the clustered substructure depends on the properties of the stellar
populations. We separate the clusters into different classes, compact (bound) clusters and
associations and compare the clustering between the different classes. In all galaxies, we find
that younger star clusters are more strongly clustered over small spatial scales and that the
clustering disappears rapidly for ages as young as a few tens of Myr. We also find gravitationally
bound clusters are systematically less clustered compared to stellar associations. Thus, compact
clusters are more evolved and have traveled significantly from their birth site within a few tens of
Myr and associations disperse over the same timescale.
Primary author
Kathryn Grasha
(University of Massachusetts)
Co-author
Daniela Calzetti
(University of Massachusetts)
