RSAA Colloquia / Seminars / Feast-of-Facts: Tuesday, 24 July 2018, 11:00-12:00; Duffield Lecture Theatre

Alyssa Sokol

"H-alpha Luminous Star Clusters in Nearby Dwarf Galaxies NGC 2366 and IC 2574: Investigating the Universality of the Stellar Initial Mass Function using SLUG"

Dwarf galaxies are low mass, low luminosity galaxies that are the building blocks of all galaxies observed today. According to this cosmological framework, these systems may have played a crucial role in re-ionizing the universe. However, star formation is an inefficient process in dwarf galaxies due to their large gas fractions, low metal content and shallow potential wells. Studies suggest that dwarfs are systematically deficient in ionizing photons, a deficit that may be linked to the underproduction of massive stars and massive star clusters. In my talk, I will discuss my recent work using Hubble Space Telescope observations of clustered sites of star formation in two nearby starburst dwarf galaxies, NGC 2366 and IC 2574. This work aims to study the H-alpha emission from young (< 10 Myrs) star clusters that host short-lived massive stars capable of producing ionizing radiation. Further understanding recent massive star formation in these low star-formation-rate dwarf galaxies will shed light on the universality of the initial mass function (IMF), or the initial distribution of stellar masses at birth, across a range of galactic environments. Though the IMF is observed to be largely non-variant throughout local star forming regions, its invariance at all size scales and environments is widely debated. Examining the IMF in the low density dwarf galaxy environment is worthwhile to investigate how efficiently these galaxies are producing massive stars and clusters compared with their more massive spiral counterparts.