I present a study of the sizes (semimajor axes) of bars in disc galaxies, combining a detailed R-band study of 65 S0–Sb galaxies with the B-band measurements of 70 Sb– Sd galaxies from Martin (1995). As has been noted before with smaller samples, bars in early-type (S0–Sb) galaxies are clearly larger than bars in late-type (Sc–Sd) galaxies; this is true both for relative sizes (bar length as fr...

We use semi-analytical modelling of galaxy formation to predict the redshift-size-evolution of elliptical galaxies. Using a simple model in which relative sizes of elliptical galaxies of a given mass correlate with the fraction of stars formed in a star burst during a major merger event, we are able to reproduce the observed redshift-size-evolution. The size evolution is a result of the amount ...

We study the role of environment in the evolution of central and satellite galaxies with the Sloan Digital Sky Survey. We begin by studying the size-mass relation, replicating previous studies, which showed no difference between the sizes of centrals and satellites at fixed stellar mass, before turning our attention to the size-core velocity dispersion (σ0) and mass-σ0 relations. By comparing t...

The local space density of galaxies as a function of their basic structural parameters –luminosity, surface brightness and scale size– is still poorly known. Our poor knowledge is the result of strong selection biases against low surface brightness and small scale size galaxies in any optically selected sample. We derive bivariate space density distributions by correcting a sample of ∼1000 loca...

Increasingly large populations of disk galaxies are now being observed at increasingly high redshifts, providing new constraints on our knowledge of how such galaxies evolve. Are these observations consistent with a cosmology in which structures form hierarchically? To probe this question, we employ SPH/N-body galaxy scale simulations of late-type galaxies. We examine the evolution of these sim...

Increasingly large populations of disk galaxies are now being observed at increasingly high redshifts, providing new constraints on our knowledge of how such galaxies evolve. Are these observations consistent with a cosmology in which structures form hierarchically? To probe this question, we employ SPH/N-body galaxy scale simulations of late-type galaxies. We examine the evolution of these sim...

Narrowband searches for Lyα emission lines are among the most effective ways to identify high-redshift galaxies. They are particularly interesting because they probe not only the galaxies themselves but also the ionization state of the intergalactic medium (IGM): nearby neutral gas efficiently absorbs Lyα photons. The observed line strengths depend on the amount by which each photon is able to ...