Numerical Galaxy Formation and Cosmology

Benjamin Moster and Ewald Puchwein

Lent term 2016

We will present state-of-the-art techniques for simulating the formation of galaxies and other cosmic structures on modern supercomputers. This includes techniques for following the gravitational collapse of structures, the hydrodynamics and a variety of star formation and feedback physics. In addition, there will be practical examples, i.e. simulations that can be performed and analyzed by the participants on their own laptop computers.

Topics that will be covered:

• Motivation for simulations & Semi-Analytic models
• Initial conditions for simulations
• Gravity algorithms & parallelization
• Hydrodynamics schemes (adaptive mesh refinement, moving-mesh, smoothed particle hydrodynamics)
• Following radiative cooling & photoheating
• Subresolution physics (star formation, supernova & AGN feedback)
• Semi-Analytic models
• How to use the Gadget2 code (examples: cosmological box, galaxy collision)

Lecture 1 (Ben, Jan 13)
topics:

• introduction to cosmological simulations and semi-analytic models
• cosmological initial conditions

Lecture 2 (Ewald, Jan 20)
topics:

• the N-body approach
• self-gravity algorithms
• parallelization
• time integration
• simulation results (collisionless runs)

Lecture 3 (Ewald, Jan 27)
topics:

• hydrodynamics & numerical hydro schemes (Eulerian & moving-mesh)
  
• advection, slope/flux limiters
• Riemann solvers

Lecture 4 (Ben, Feb 3)
topics:

• smoothed particle hydrodynamics
• radiative cooling/heating
• subresolution models for star formation and feedback

Lecture 5 (Ben, Feb 10)
topics:

• halo and subhalo finders
• semi-analytic galaxy formation models
• empirical galaxy formation models

Lecture 6 (Ewald, Feb 17)
topics:

• Exercise 1: Performing a cosmological simulation with the Gadget-2 code

Lecture 7 (Ben, Feb 24)
topics:

• Exercise 2: Galaxy mergers

Lecture 8 (Ewald, Mar 2)
topics:

• Exercise 1 - part 2: Analyzing a cosmological simulation (halo finding, halo mass function, maps)

The Gadget-2 code

In the second half of the course we will do some exercises with the Gadget-2 cosmological simulation code. It can be downloaded here: