Beecroft Institute for Particle Astrophysics and Cosmology

Abstract:

This contribution discusses the challenges of implementing star formation and stellar feedback processes in galaxy simulations. Insufficient computational power and numerous poorly understood physical processes, force simulations to adopt sub-grid models of the interstellar medium. These may crucially bias results. We advocate for smaller (similar to kiloparsec) scale simulations of the interstellar medium to guide the development of sub-grid models in larger simulations. In this vein, I show results on ever increasing scales ranging from similar to 1 h(-1) kpc(3) ISM simulations, to a 1 h(-1) Mpc(3) simulation of a galaxy forming at evolved high redshift, to a larger cosmological volume, 6.25 h(-1) Mpc(3), down to redshift 3. We find that galactic winds can be powered by SN implemented as point explosions in high redshift galaxies simulated with sufficient spatial resolution. Galaxies at lower redshift require alternative sub-grid feedback models and we present one possible solution to generate winds from galaxies at redshift similar to 4.

Abstract:

This paper presents MoLUSC, a new method for generating mock galaxy catalogs from a large scale ($\approx 1000^3$ Mpc$^3$) dark matter simulation, that requires only modest CPU time and memory allocation. The method uses a small-scale ($\approx 256^3$ Mpc$^3$) dark matter simulation on which the \galics semi-analytic code has been run in order to define the transformation from dark matter density to galaxy density transformation using a probabilistic treatment. MoLUSC is then applied to a large-scale dark matter simulation in order to produce a realistic distribution of galaxies and their associated spectra. This permits the fast generation of large-scale mock surveys using relatively low-resolution simulations. We describe various tests which have been conducted to validate the method, and demonstrate a first application to generate a mock Sloan Digital Sky Survey redshift survey.