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We present a study of metal-enriched halo gas traced by Mg II and C IV absorption at z < 2 in the MUSE Analysis of Gas around Galaxies survey and the Quasar Sightline and Galaxy Evolution survey. Using these large and complete galaxy surveys in quasar fields, we study the dependence of the metal distribution on galaxy properties and overdensities, out to physical projected separations of 750 kpc. We find that the cool, low-ionization gas is significantly affected by the environment across the full redshift range probed, with approximate to 2-3 times more prevalent and stronger Mg II absorption in higher overdensity group environments and in regions with greater overall stellar mass and star formation rates. Complementary to these results, we have further investigated the more highly ionized gas as traced by CIV absorption, and found that it is likely to be more extended than the Mg II gas, with approximate to 2 times higher covering fraction at a given distance. We find that the strength and covering fraction of C IV absorption show less significant dependence on galaxy properties and environment than the Mg II absorption, but more massive and star-forming galaxies nevertheless also show approximate to 2 times higher incidence of C IV absorption. The incidence of Mg II and C IV absorption within the virial radius shows a tentative increase with redshift, being higher by a factor of approximate to 1.5 and approximate to 4, respectively, at z > 1. It is clear from our results that environmental processes have a significant impact on the distribution of metals around galaxies and need to be fully accounted for when analysing correlations between gaseous haloes and galaxy properties.

We present half-light sizes measured from Ha emission tracing star formation in 281 star-forming galaxies from the KMOS3D survey at 0.7 less than or similar to z less than or similar to 2.7. Sizes are derived by fitting 2D exponential disk models, with bootstrap errors averaging 20%. H alpha sizes are a median (mean) of 1.19 (1.26) times larger than those of the stellar continuum-which, due to radial dust gradients, places an upper limit on the growth in stellar size via star formation-with just similar to 43% intrinsic scatter. At fixed continuum size the H alpha size shows no residual trend with stellar mass, star formation rate, redshift, or morphology. The only significant residual trend is with the excess obscuration of H alpha by dust, at fixed continuum obscuration. The scatter in continuum size at fixed stellar mass is likely driven by the scatter in halo spin parameters. The stability of the ratio of H alpha size to continuum size demonstrates a high degree of stability in halo spin and in the transfer of angular momentum to the disk over a wide range of physical conditions and cosmic time. This may require local regulation by feedback processes. The implication of our results, as we demonstrate using a toy model, is that our upper limit on star-formation-driven growth is sufficient only to evolve star-forming galaxies approximately along the observed size-mass relation, consistent with the size growth of galaxies at constant cumulative comoving number density. To explain the observed evolution of the size-mass relation of star-forming disk galaxies, other processes, such as the preferential quenching of compact galaxies or galaxy mergers, may be required.