EHMVSIMF · INVESTIGATING EVIDENCE OF HIGH-MASS VARIATIONS OF THE STELLAR INITIAL MASS FUNCTION

INVESTIGATING EVIDENCE OF HIGH-MASS VARIATIONS OF THE STELLAR INITIAL MASS FUNCTION

Star clusters comprise thousands, even millions, of stars, some like the sun, some are giants, and some are dwarfs. Many millions of star clusters together form a galaxy, and the Universe contains billions of galaxies. Therefore star clusters, in a way, are a fundamental constituent of a galaxy. One of the defining questions in the study of galaxy evolution is the assumption that stars formed within star clusters with a preferred mass distribution independent of time and environment. This preferred birth mass distribution of stars, called the stellar initial mass function (IMF), is intimately related to the star formation processes within a galaxy, underlying much of its evolution; therefore it is essential to confirm the true nature of the IMF to advance the field. While significant advances in understanding mainly the low-mass stellar IMF variations have been made in the past decade, relatively a little attention has been paid to the high-mass IMF. We aimed to utilise innovative techniques, the latest high-resolution observations, stellar population and photoionisation codes and simulations to study starbursting regions within galaxies that are hosts to high gas pressure and turbulent environments. These types of environments are thought to be responsible for determining the form of the high-mass IMF, so studying them will allow us to disentangle many degeneracies that generally affect star formation studies. The overall objectives include developing robust techniques to tightly constrain star formation properties and histories of starbursting regions to characterise the evolution and progression of star formation within galaxies, and comparisons with simulated observations. The data for the project was drawn from the Antennae observing programme of the MUSE (Multi Unit Spectroscopic Explorer) consortium as well as from other European and Australasian-led surveys such as GAMA (Galaxy And Mass Assembly) and SAMI (Sydney-AAO Multi-Object IFU). One of the primary outcomes of the project is that we have developed a comprehensive and self-consistent suit of high-resolution models specifically tailored to fit spectroscopic observations of starbursting regions. The model fitting process is designed to use a wide range of information in a given spectrum of a starbursting region to simultaneously converge on the best-fitting physical parameters, such as star formation history, the metallicity of gas and stars, the age of the dominant young and old stellar populations, and electron densities and temperatures.

Data: CORDIS, © European Union