Moving mesh cosmology: numerical techniques and global statistics

By M. Vogelsberger, D. Sijacki, D. Keres̆, Volker Springel, Lars Hernquist HarvardCfA, Uc Berkeley, U. Diego, Hits. 2011

177 citations recorded by the source corpus.

We present the first hydrodynamical simulations of structure formation using the new moving mesh code arepo and compare the results with gadget simulations based on a traditional smoothed particle hydrodynamics (SPH) technique. The two codes share the same Tree-PM gravity solver and include identical subresolution physics for the treatment of star formation, but employ different methods to solve the equations of hydrodynamics. This allows us to assess the impact of hydro-solver uncertainties on the results of cosmological studies of galaxy formation. In this paper, we focus on predictions for global baryon statistics, such as the cosmic star formation rate density, after we introduce our simulation suite and numerical methods. Properties of individual galaxies and haloes are examined by Keres et al., while a third paper by Sijacki et al. uses idealized simulations to analyse in more detail the differences between the hydrodynamical schemes. We find that the global baryon statistics differ significantly between the two simulation approaches. arepo shows systematically higher star formation rates at late times, lower mean temperatures averaged over the simulation volume and different gas mass fractions in characteristic phases of the intergalactic medium, in particular a reduced amount of hot gas. Although both hydrodynamical codes use the same implementation of cooling and yield an identical dark matter halo mass function, more gas cools out of haloes in arepo compared with gadget towards low redshifts, which results in corresponding differences in the late-time star formation rates of galaxies. We show that this difference is caused by a higher heating rate with SPH in the outer parts of haloes, owing to viscous dissipation of SPH's inherent sonic velocity noise and SPH's efficient damping of subsonic turbulence injected in the halo infall region, and because of a higher efficiency of gas stripping in arepo. As a result of such differences, arepo leads also to more disc-like morphologies in the moving mesh calculation compared to gadget. Our results hence indicate that inaccuracies in hydrodynamic solvers can lead to comparatively large systematic differences even at the level of predictions for the global state of baryons in the universe.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/b66cb6eaf0724a1e59bdb42c333324a964657d8c

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

Star formation in galaxy mergers with realistic models of stellar feedback and the interstellar medium (2012, background): “…mesh code AREPO (Springel 2010) have called into question the reliability of smoothed particle hydrodynamics (SPH) for some problems related to galaxy formation in a cosmological context (Torrey et al. 2012b; Bauer & Springel 2012; Kereš et al. 2012; Sijacki et al. 2012; Vogelsberger et al. 2012).”
A model for cosmological simulations of galaxy formation physics: multi-epoch validation (2013, methodology): “(Although we emphasise that this ’advantage’ of SPH comes at the expense of an inaccurate integration of the mass continuity equation (see, e.g., Vogelsberger et al. 2012).)”
Improving the convergence properties of the moving-mesh code AREPO (2015, methodology): “These new methods have matured into interesting alternative codes that have already been widely applied in cosmological simulations of structure formation (e.g. Vogelsberger et al. 2012; Sijacki et al. 2012; Marinacci et al. 2013; Vogelsberger et al. c© 0000 RAS ar X iv :1 50 3.”
A new class of accurate, mesh-free hydrodynamic simulation methods (2014, background): “…to that in GADGET and AREPO, modulo welltested improvements and optimizations, and this has been tested in a huge variety of situations (see e.g. Springel 2005; Springel et al. 2005b; Hayward et al. 2011; Vogelsberger et al. 2012; Scannapieco et al. 2012; Kim et al. 2013, and references therein).”
Star formation sustained by gas accretion (2014, background): “Similarly, Kereš et al. (2012), Vogelsberger et al. (2012) and Sijacki et al. (2012) found higher star formation rates with AREPO than SPH because realistic turbulent cascades in AREPO channel the energy to denser scales where it dissipates at a greater rate.”
Galaxies on FIRE (Feedback In Realistic Environments): stellar feedback explains cosmologically inefficient star formation (2013, methodology): “…the results of grid codes and older SPH methods (such as that in Springel & Hernquist 2002) for certain problems (especially sub-sonic fluid mixing instabilities; see Agertz et al. 2007; Kitsionas et al. 2009; Bauer & Springel 2012; Vogelsberger et al. 2012; Sijacki et al. 2012; Kereš et al. 2012).”
Galaxy pairs in the Sloan Digital Sky Survey – VI. The orbital extent of enhanced star formation in interacting galaxies (2013, methodology): “Recent studies have shown improvements in the ability of galax- ies to form and maintain gas–rich discs in cosmological simulations (Vogelsberger et al. 2012; Torrey et al. 2012) which may allow for direct measures of the SFR enhancement for paired galaxies using analogous methods to those applied…”
Galaxy morphology and star formation in the Illustris Simulation at z = 0 (2015, methodology): “Using the Arepo code for gravity and gas dynamics (Springel 2010), these simulations evolve simultaneously the gas, stars, and dark matter components from cosmological initial conditions (Vogelsberger et al. 2012; Kereš et al. 2012; Sijacki et al. 2012).”
Introducing the Illustris Project: the evolution of galaxy populations across cosmic time (2014, methodology): “…shown this method to be advantageous in terms of accuracy compared to the traditional methods of smoothed particle hydrodynamics (SPH) and adaptive mesh refinement (AMR; Kereš et al. 2012; Sijacki et al. 2012; Torrey et al. 2012; Vogelsberger et al. 2012; Genel et al. 2013; Nelson et al. 2013).”
The formation of massive, compact galaxies at z = 2 in the Illustris simulation (2014, methodology): “…a hydrodynamic treatment of gas using the moving-mesh code AREPO (Springel 2010), which has demonstrated advantages on cosmological galaxy formation problems (Vogelsberger et al. 2012; Kereš et al. 2012; Torrey et al. 2012; Nelson et al. 2013) over traditional smoothed particle hydrodynamics codes.”
Simulations of magnetic fields in isolated disc galaxies (2012, methodology): “The refinement and derefinement operations are carried out as described in Springel (2010) and Vogelsberger et al. (2012).”
The merger rate of galaxies in the Illustris simulation: a comparison with observations and semi-empirical models (2015, methodology): “…in this work, we have also calculated the halo merger rate for all the different feedback implementations described in Vogelsberger et al. (2013), as well as for the GADGET and AREPO runs described in Vogelsberger et al. (2012), which also resulted in no significant difference between any of them.”
A general class of Lagrangian smoothed particle hydrodynamics methods and implications for fluid mixing problems (2012, background): “…cosmological times, or allowing for different galaxy conditions because of the integrated effects of different heating/cooling efficiencies as gas actually accretes into halos, however, these small differences can easily build up into more significant divergence (see e.g. Vogelsberger et al. 2011).”
THE CONNECTION BETWEEN GALAXIES AND DARK MATTER STRUCTURES IN THE LOCAL UNIVERSE (2012, background): “…direct approach to understanding the relationship between galaxies and halos is to run a full, hydrodynamic simulation, which may explicitly include the effects of star formation and feedback (e.g., Bryan & Norman 1998; Springel & Hernquist 2003; Vogelsberger et al. 2012 and references therein).”
Moving mesh cosmology: tracing cosmological gas accretion (2013, methodology): “In general, Vogelsberger et al. (2012) showed the increase in high redshift global star formation rates due to better resolving dense gas in low mass haloes.”
FIRE-2 simulations: physics versus numerics in galaxy formation (2017, result): “Similar conclusions have been reached in previous comparisons of movingmesh and fixed-grid codes to SPH, but with simpler treatments of ISM cooling/phases and feedback (Torrey et al. 2012; Sijacki et al. 2012; Kereš et al. 2012; Vogelsberger et al. 2012).”