The influence of star clusters on galactic disks: new insights on star-formation in galaxies

TL;DR

This paper explores how star clusters influence galaxy evolution, star formation, and galactic structures, proposing that understanding cluster physics can lead to paradigm shifts in galaxy evolution models.

Contribution

It introduces the IGIMF theory's implications for galaxy evolution, linking star cluster properties with galaxy-wide star formation and gas depletion timescales.

Findings

Dwarf irregular galaxies share gas-depletion timescales with disk galaxies.

Radial Halpha cutoff can be explained without a star-formation cutoff.

Star cluster physics impacts galaxy evolution models significantly.

Abstract

Stars form in embedded star clusters which play a key role in determining the properties of a galaxy's stellar population. Physical mechanisms discussed in this paper are runaway stars shot out from young clusters, binary-star disruption in clusters, gas blow-out from clusters and the origin of thick galactic disks. I emphasise that the SNIa rate per low-mass star depends on the star-clusters formed in a galaxy and I discuss the IGIMF theory. Based on the IGIMF theory, the re-calibrated Halpha-luminosity--SFR relation implies dwarf irregular galaxies to have the same gas-depletion time-scale as major disk galaxies, suggesting a major change in our understanding of dwarf-galaxy evolution. The IGIMF-theory also naturally leads to the observed radial Halpha cutoff in disk galaxies without a radial star-formation cutoff. It emerges that the thorough understanding of the physics and distribution of star clusters may be leading to a major paradigm shift in our understanding of galaxy evolution.