General

        
Magneticum Pathfinder aims to follow the formation of cosmological structures in a so far unaccomplished level of detail by performing a set of large scale and high resolution simulations, taking into account many physical processes to allow detailed comparison to a variety of multi-wavelength observational data. Such simulation need to incorporate a detailed description of various, complex, non-gravitational, physical processes, which determine the evolution of the cosmic baryons and impact their observational properties.

Cosmology

Using WMAP7 cosmology taken from Komatsu et al. 2010:
  • Total matter density Ohm0=0.272 (16.8% baryons)
  • Cosmological constant Lam0=0.728
  • Hubble constant H0=70.4
  • Index of the primordial power spectrum n=0.963
  • Overall normalisation of the power spectrum   Sigma8=0.809  

Physics included

  • cooling, star formation, winds (Springel & Hernquist 2003)
  • Metals, Stellar population and chemical enrichment
    SN-Ia, SN-II, AGB (Tornatore et al. 2003/2006)
    new cooling tables (Wiersma et al. 2009)
  • Black Holes and AGN feedback (Springel & Di Matteo 2006, Fabjan et al. 2010)
    various imrovements (Hirschmann et al. 2014)
  • Thermal Conduction (1/20th Spitzer) (Dolag et al. 2004)
  • Low viscosity scheme to track turbulence (Dolag et al. 2005)
    various improvements (Beck et al. 2014, in prep)
  • Higher order SPH Kernels (Dehnen & Aly 2012)
  • Magnetic Fields (passive) (Dolag & Stasyszyn 2009)

Simulations

Magneticum Pathfinder & Magneticum

 Box1Box2Box3Box4Box5
[Mpc/h]8963521284818
mr2*152632*59432*21632*813 
hr 2*158432*57632*21632*813
uhr  2*153632*57632*2163
xhr   2*153632*5763
Table 1: Number of particles used in the Magneticum Pathfinder simulations. The gray entries mark future, planned simulations.

 mdmmgasepsdmepsgasepsstars
mr1.3e102.6e910105
hr6.9e81.4e83.753.752
uhr3.6e77.3e61.41.40.7
xhr1.9e63.9e50.450.450.25
Table 2: Mass of dm and gas particles (in Msol/h) at the different resolution levels and the according softenings (in kpc/h) used.

 Box0Box2b
[Mpc/h]2688640
mr2*45363 
hr 2*28803
Table 3: Number of particles used in the Magneticum simulations.

Extra Runs

Dark Matter control simulations

We performed dark matter only control runs for various of the Boxes. To avoid a different sampling of the initial density fluctuations, all these runs where done using two dark matter particle species, e.g. by treating the gas particles as dark matter only particles. Available dark mater only simulations include Box0/mr, Box3/hr, Box4/uhr and Box5/xhr. The imprint of teh baryonic physics on the mass function of haloes as covered by the simulation set can be seen in the figure at the right.

MHD simulations

Currently there are varius simulations of Box3/hr as full MHD simulations available, including simulations combining cooling and star-formation with MHD. They are probing different scenarious for the origin of the magnetic field within the LSS.

Post processing

On the fly post-processing

Similar to Saro et al. (2006), we compute the luminosities of our simulated galaxies on the fly using the stellar population synthesis model of Bruzual & Charlot (2007) in different spectral bands (u,V,G,r,i,z,Y,J,H,K,L,M) as well as their star-formation rate and HI content. Following Nuzza et. al. 2010 we also take dust attenuation into account when computing the observer frame luminosities. The attenuation is estimated from the radial dust profile, computed from the metal and HI profile of the galaxies.

Data Management

All simulations dumps have implemented an algorithm which sort the particles among the CPUs among a space filling curve and produces an auxiliary file which allows to identify the sub-data volume elements of any stored property among all particle species associated to each element of the space filling curve used. Finally there is a super index build which allos to identify the sub snapshots which belongs to the different parts of the space filing curve. This allows to effectively collect all data associated to a given volume in space (defined by the elements of the space filling curve it occupies) with a minimum of reading overhead (see figure on the right).