We investigate the properties of damped Lyman α systems (DLAs) using high-resolution and large box-size cosmological hydrodynamical simulations of a cold dark matter model. The numerical code used is a modification of GADGET-2 with a self-consistent implementation of the metal enrichment mechanism. We explore the numerical convergence of some relevant physical quantities and we vary the parameters describing the properties of galactic winds, the initial stellar mass function, the linear dark matter power spectrum and the metal enrichment pattern of the intergalactic medium (IGM) around DLAs. We focus on the properties of dark matter haloes that are likely to be the hosts of DLAs systems: we predict relatively low star formation rates (∼0.01-0.1 M yr −1 ) and metallicities around 0.1 Z , at least for the bulk of our haloes of masses between 10 9 and 10 10 h −1 M hosting DLAs. For more massive haloes metallicities and star formation rates depend on the specific wind model. We find that strong galactic winds with speed of about 600 km s −1 , in an energy-driven wind scenario, are needed in order to match the observed column density distribution function for DLAs and the evolution of the neutral hydrogen content with redshift. The momentum-driven implementation of the galactic wind model, that relates the speed and mass load in the wind to the properties of the dark matter haloes, shows a behaviour which is intermediate between the energy-driven galactic winds of small (∼100 km s −1 ) and large (∼600 km s −1 ) velocities. At z = 3 the contribution of haloes of masses between 10 9 and 10 10 h −1 M , for DLAs below 10 20.8 cm −2 , to the column density distribution function, is significant. By interpolating physical quantities along line-of-sights through massive haloes we qualitatively show how different galactic wind models impact on the IGM around DLAs. Furthermore, we analyse statistics related to the velocity widths of Si II associated to DLAs: while the expanding shells of gaseous matter associated to the wind can account for the observed velocities, the metallicity in the wind seems to be rather clumpy and this produces an underestimation of the observed velocity widths. We outline possible solutions to this problem.

We investigate the relationship between stellar and gas specific angular momentum j, stellar mass M * and optical morphology for a sample of 488 galaxies extracted from the SAMI Galaxy Survey. We find that j, measured within one effective radius, monotonically increases with M * and that, for M * >10 9.5 M , the scatter in this relation strongly correlates with optical morphology (i.e., visual classification and Sérsic index). These findings confirm that massive galaxies of all types lie on a plane relating mass, angular momentum and stellar light distribution, and suggest that the largescale morphology of a galaxy is regulated by its mass and dynamical state. We show that the significant scatter in the M * − j relation is accounted for by the fact that, at fixed stellar mass, the contribution of ordered motions to the dynamical support of galaxies varies by at least a factor of three. Indeed, the stellar spin parameter (quantified via λ R ) correlates strongly with Sérsic and concentration indices. This correlation is particularly strong once slow-rotators are removed from the sample, showing that late-type galaxies and early-type fast rotators form a continuous class of objects in terms of their kinematic properties.

We present the ∼800 star formation rate maps for the SAMI Galaxy Survey based on Hα emission maps, corrected for dust attenuation via the Balmer decrement, that are included in the SAMI Public Data Release 1. We mask out spaxels contaminated by non-stellar emission using the [O III]/Hβ, [N II]/Hα, [S II]/Hα, and [O I]/Hα line ratios. Using these maps, we examine the global and resolved star-forming main sequences of SAMI galaxies as a function of morphology, environmental density, and stellar mass. Galaxies further below the star-forming main sequence are more likely to have flatter star formation profiles. Early-type galaxies split into two populations with similar stellar masses and central stellar mass surface densities. The main sequence population has centrally-concentrated star formation similar to late-type galaxies, while galaxies >3σ below the main sequence show significantly reduced star formation most strikingly in the nuclear regions. The split populations support a two-step quenching mechanism, wherein halo mass first cuts off the gas supply and remaining gas continues to form stars until the local stellar mass surface density can stabilize the reduced remaining fuel against further star formation. Across all morphologies, galaxies in denser environments show a decreased specific star formation rate from the outside in, supporting an environmental cause for quenching, such as ram-pressure stripping or galaxy interactions.

We study the role of feedback from supernovae and black holes in the evolution of the star formation rate function (SFRF) of z ∼ 4 − 7 galaxies. We use a new set of cosmological hydrodynamic simulations, ANGUS (AustraliaN GADGET-3 early Universe Simulations), run with a modified and improved version of the parallel TreePM-smoothed particle hydrodynamics code GADGET-3 called P-GADGET3(XXL), that includes a self-consistent implementation of stellar evolution and metal enrichment. In our simulations both Supernova (SN) driven galactic winds and Active Galactic Nuclei (AGN) act simultaneously in a complex interplay. The SFRF is insensitive to feedback prescription at z > 5, meaning that it cannot be used to discriminate between feedback models during reionisation. However, the SFRF is sensitive to the details of feedback prescription at lower redshift. By exploring different SN driven wind velocities and regimes for the AGN feedback, we find that the key factor for reproducing the observed SFRFs is a combination of "strong" SN winds and early AGN feedback in low mass galaxies. Conversely, we show that the choice of initial mass function and inclusion of metal cooling have less impact on the evolution of the SFRF. When variable winds are considered, we find that a non-aggressive wind scaling is needed to reproduce the SFRFs at z 4. Otherwise, the amount of objects with low SFRs is greatly suppressed and at the same time winds are not effective enough in the most massive systems.