Abstract

Modern surveys provide an enormous resource for those trying to understand the formation and structure of galaxies. I present the results of an analysis of 2000 massive Sloan ellipticals. Comparing dynamical and stellar masses reveals that the inner regions of these systems are baryon-dominated. We further develop a method, based on adiabatic contraction, to constrain the initial dark matter profile of these systems, finding a log-normal distribution in concentration which compares well with semi-analytic models.

Like all massive ellipticals, it appears that the stars in these systems formed early, and so novel methods of detecting star formation in the early Universe are of interest. Our knowledge of star formation in the Milky Way is entirely dependent on astrochemical models. Finding the sites of star formation, constraining the cosmic ray rate or unravelling the dynamical history of a star-forming core requires an understanding of both the physics and the chemistry involved. With the discovery of substantial reservoirs of molecular gas in galaxies out to redshifts beyond 6, the challenge is to successfully apply local models to these distant and exotic systems. Doing so produces surprising results; we predict that - with the correct choice of molecule - it would be possible to constrain the star formation history of early galaxies and shed light on such questions as the mass of the first stars, even with existing telescopes.

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