Evolution of star formation and gas

TL;DR

This paper reviews observations and models of star formation in molecular clouds across different galaxies, synthesizing low- and high-redshift data to enhance understanding of galaxy evolution and prepare for upcoming FIR and mm/submm observations.

Contribution

It provides a comprehensive synthesis of star formation observations and models, including a new coherent discussion on dust heating and radiative transfer for interpreting IR emissions.

Findings

Developed an intuitive model for galaxy evolution.

Synthesized low- and high-redshift star formation data.

Prepared frameworks for interpreting FIR and mm/submm observations.

Abstract

In these lectures I review observations of star-forming molecular clouds in our Galaxy and nearby galaxies to develop a physical intuition for understanding star formation in the local and high-redshift Universe. A lot of this material is drawn from early work in the field since much of the work was done two decades ago and this background is not generally available in the present literature. I also attempt to synthesise our well-developed understanding of star formation in low-redshift galaxies with constraints from theory and observations at high redshift to develop an intuitive model for the evolution of galaxy mass and luminosity functions in the early Universe. The overall goal of this contribution is to provide students with background helpful for analysis of far-infrared (FIR) observations from Herschel and millimetre/submillimetre (mm/submm) imaging with ALMA (the Atacama Large Millimetre/submillimetre Array). These two instruments will revolutionise our understanding of the interstellar medium (ISM) and associated star formation and galaxy evolution, both locally and in the distant Universe. To facilitate interpreting the FIR spectra of Galactic star-forming regions and high-redshift sources, I develop a model for the dust heating and radiative transfer in order to elucidate the observed infrared (IR) emissions. I do this because I am not aware of a similar coherent discussion in the literature.