Supernova (SN) feedback is one of the key processes shaping the interstellar medium (ISM) of galaxies. SNe contribute to (and in some cases may dominate) driving turbulence in the ISM and accelerating galactic winds. Modern cosmological simulations have sufficient resolution to capture the main structures in the ISM of galaxies, but are typically still not capable of explicitly resolving all of the small-scale stellar feedback processes, including the expansion of supernova remnants (SNRs). We perform a series of controlled three-dimensional hydrodynamic (adaptive mesh refinement) simulations of single SNRs expanding in an inhomogeneous density field with statistics motivated by those of the turbulent ISM. We use these to quantify the momentum and thermal energy injection from SNe as a function of spatial scale and the density, metallicity, and structure of the ambient medium. We develop a series of analytic formulae that we fit to the simulations. These formulae can be used as a basis for a more predictive sub-resolution model for SN feedback for galaxy formation simulations. We then use simulations of multiple, stochastically driven SNe that resolve the key phases of SNRs to test the sub-resolution model, and show that it accurately captures the turbulent kinetic energy and thermal energy in the ISM. By contrast, proposed SN feedback models in the literature based on 'delayed cooling' significantly overpredict the late-time thermal energy and momentum in SNRs.

We use 1‐kpc resolution cosmological Adaptive Mesh Refinement (AMR) simulations of a Virgo‐like galaxy cluster to investigate the effect of feedback from supermassive black holes on the mass distribution of dark matter, gas and stars. We compared three different models: (i) a standard galaxy formation model featuring gas cooling, star formation and supernovae feedback, (ii) a ‘quenching’ model for which star formation is artificially suppressed in massive haloes and finally (iii) the recently proposed active galactic nucleus (AGN) feedback model of Booth and Schaye. Without AGN feedback (even in the quenching case), our simulated cluster suffers from a strong overcooling problem, with a stellar mass fraction significantly above observed values in M87. The baryon distribution is highly concentrated, resulting in a strong adiabatic contraction (AC) of dark matter. With AGN feedback, on the contrary, the stellar mass in the brightest cluster galaxy (BCG) lies below observational estimates and the overcooling problem disappears. The stellar mass of the BCG is seen to increase with increasing mass resolution, suggesting that our stellar masses converge to the correct value from below. The gas and total mass distributions are in better agreement with observations. We also find a slight deficit (∼10 per cent) of baryons at the virial radius, due to the combined effect of AGN‐driven convective motions in the inner parts and shock waves in the outer regions, pushing gas to Mpc scales and beyond. This baryon deficit results in a slight adiabatic expansion of the dark matter distribution that can be explained quantitatively by AC theory.

We analyze the IllustrisTNG simulations to study the mass, volume fraction and phase distribution of gaseous baryons embedded in the knots, filaments, sheets and voids of the Cosmic Web from redshift z = 8 to redshift z = 0. We find that filaments host more starforming gas than knots, and that filaments also have a higher relative mass fraction of gas in this phase than knots. We also show that the cool, diffuse Intergalactic Medium (IGM; T < 10 5 K, n H < 10 −4 (1 + z) cm −3 ) and the Warm-Hot Intergalactic Medium (WHIM; 10 5 K < T < 10 7 K, n H < 10 −4 (1 + z) cm −3 ) constitute ∼ 39% and ∼ 46% of the baryons at redshift z = 0, respectively. Our results indicate that the WHIM may constitute the largest reservoir of missing baryons at redshift z = 0. Using our Cosmic Web classification, we predict the WHIM to be the dominant baryon mass contribution in filaments and knots at redshift z = 0, but not in sheets and voids where the cool, diffuse IGM dominates. We also characterise the evolution of WHIM and IGM from redshift z = 4 to redshift z = 0, and find that the mass fraction of WHIM in filaments and knots evolves only by a factor ∼ 2 from redshift z = 0 to z = 1, but declines faster at higher redshift. The WHIM only occupies 4 − 11% of the volume at redshift 0 z 1. We predict the existence of a significant number of currently undetected OVII and NeIX absorption systems in cosmic filaments which could be detected by future X-ray telescopes like Athena.

We use three-dimensional hydrodynamic simulations of vertically stratified patches of galactic discs to study how the spatio-temporal clustering of supernovae (SNe) enhances the power of galactic winds. SNe that are randomly distributed throughout a galactic disc drive inefficient galactic winds because most supernova remnants lose their energy radiatively before breaking out of the disc. Accounting for the fact that most star formation is clustered alleviates this problem. Super-bubbles driven by the combined effects of clustered SNe propagate rapidly enough to break out of galactic discs well before the clusters' SNe stop going off. The radiative losses postbreakout are reduced dramatically and a large fraction ( 0.2) of the energy released by SNe vents into the halo powering a strong galactic wind. These energetic winds are capable of providing strong preventative feedback and eject substantial mass from the galaxy with outflow rates on the order of the star formation rate. The momentum flux in the wind is only of order that injected by the SNe, because the hot gas vents before doing significant work on the surroundings. We show that our conclusions hold for a range of galaxy properties, both in the local Universe (e.g., M82) and at high redshift (e.g., z ∼ 2 star forming galaxies). We further show that if the efficiency of forming star clusters increases with increasing gas surface density, as suggested by theoretical arguments, the condition for star cluster-driven super-bubbles to break out of galactic discs corresponds to a threshold star formation rate surface density for the onset of galactic winds ∼ 0.03 M yr −1 kpc −2 , of order that observed.