Moving mesh cosmology: tracing cosmological gas accretion

By D. Nelson, M. Vogelsberger, Shy Genel, D. Sijacki, D. Keres̆, Volker Springel, Lars Hernquist HarvardCfA, U. Diego, Hits. 2013

266 citations recorded by the source corpus.

We investigate the nature of gas accretion onto haloes and galaxies at z=2 using cosmological hydrodynamic simulations run with the moving mesh code AREPO. Implementing a Monte Carlo tracer particle scheme to determine the origin and thermodynamic history of accreting gas, we make quantitative comparisons to an otherwise identical simulation run with the smoothed particle hydrodynamics (SPH) code GADGET-3. Contrasting these two numerical approaches, we find significant physical differences in the thermodynamic history of accreted gas in haloes above 10^10.5 solar masses. In agreement with previous work, GADGET simulations show a cold fraction near unity for galaxies forming in massive haloes, implying that only a small percentage of accreted gas heats to an appreciable fraction of the virial temperature during accretion. The same galaxies in AREPO show a much lower cold fraction, <20% in haloes above 10^11 solar masses. This results from a hot gas accretion rate which, at this same halo mass, is an order of magnitude larger than with GADGET, while the cold accretion rate is also lower. These discrepancies increase for more massive systems, and we explain both as due to numerical inaccuracies in the standard formulation of SPH. We also observe that the relatively sharp transition from cold to hot mode dominated accretion, at a halo mass of ~10^11, is a consequence of comparing past gas temperatures to a constant threshold value independent of virial temperature. Examining the spatial distribution of accreting gas, we find that gas filaments in GADGET tend to remain collimated and flow coherently to small radii, or artificially fragment and form a large number of purely numerical "blobs". Similar gas streams in AREPO show increased heating and disruption at 0.25-0.5 virial radii and contribute to the hot gas accretion rate in a manner distinct from classical cooling flows.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/8088cc9b244978838ebcba401600423e4f924a2d

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Citations in the corpus

Star formation sustained by gas accretion (2014, background): “For example, the moving mesh code AREPO gets less purely cold gas at high halo mass than do smoothed particle hydrodynamics (SPH) codes because cold filaments break apart and mix with hot halo gas more readily in AREPO (Nelson et al. 2013).”
Compaction and quenching of high-z galaxies in cosmological simulations: blue and red nuggets (2014, background): “The detailed thermal history of the streams in the inner halo (Ceverino, Dekel & Bournaud 2010; Nelson et al. 2013) does not make a difference, as long as the discs are fed with cold gas at the levels consistent with the observed high SFR and gas fraction.”
THE BIMODAL METALLICITY DISTRIBUTION OF THE COOL CIRCUMGALACTIC MEDIUM AT z ≲ 1 (2013, background): “These simulations show in particular some critical differences in the covering factors of LLS and DLA and how galaxies get their gas (Kereš et al. 2012; Bird et al. 2013; Nelson et al. 2013).”
First results from the TNG50 simulation: galactic outflows driven by supernovae and black hole feedback (2019, methodology): “…mass outflow rates two orthogonal techniques exist: (i) deriving instantaneous fluxes based on gas kinematics at one point in time (e.g. Ocvirk et al. 2008), and (ii) deriving mass fluxes by tracking the Lagrangian evolution of gas mass across two distinct points in time (e.g. Nelson et al. 2013).”
The merger rate of galaxies in the Illustris simulation: a comparison with observations and semi-empirical models (2015, background): “A less approximate treatment is in principle possible – although not done here – by following Monte Carlo tracer particles instead of gas cells (Nelson et al. 2013; Genel et al. 2013).”
The star formation main sequence and stellar mass assembly of galaxies in the Illustris simulation (2014, background): “For example, if the phase structure or metal content of the hot halo gas is incorrect, gas inflow rates could end up being inaccurate (Nelson et al. 2013; Hayward et al. 2014).”
Toy models for galaxy formation versus simulations (2013, methodology): “…to new codes using a moving unstructured grid (Bauer & Springel 2012), but the latter are currently limited to significantly lower resolution, on the order of ∼ 1 kpc (e.g., Nelson et al. 2013), which is not sufficient for tracing the key processes of disc instabilities or the evolution of streams.”
Dusty Star Forming Galaxies at High Redshift (2014, unknown): “In many ways, the different methods agree between one another, though in others there can be stark differences (see, e.g., Nelson et al., 2013, for a recent example).”
AN INTENSELY STAR-FORMING GALAXY AT z ∼ 7 WITH LOW DUST AND METAL CONTENT REVEALED BY DEEP ALMA AND HST OBSERVATIONS (2013, background): “Although Himiko’s halo mass does likely lie in the range where cold accretion could be possible, we note that some recent simulations have cast doubt on the efficiency of this mode of assembly (Nelson et al. 2013; Vogelsberger et al. 2013).”
Introducing the Illustris Project: the evolution of galaxy populations across cosmic time (2014, methodology): “…sharp transitions or bimodalities are common and probably useful, in various contexts, for interpreting observational data and constructing analytical models, hydrodynamical cosmological simulations often show more subtle, smoother transitions between limiting regimes (e.g. Nelson et al. 2013).”
THE ERA OF STAR FORMATION IN GALAXY CLUSTERS (2013, background): “The observed starbursts are not likely to be driven by cold-mode accretion (e.g., Kereš et al. 2005; Dekel and Birnboim 2006; Dekel et al. 2009; Nelson et al. 2013) as these cluster galaxies reside within a hot ICM that should prevent cold streams to all galaxies except possibly the BCG.”
The formation of disc galaxies in high-resolution moving-mesh cosmological simulations (2013, background): “This greatly modifies how galaxies acquire their gas in large haloes, suppressing the relative importance of hot mode gas accretion in these systems (Nelson et al. 2013).”
The EAGLE project: Simulating the evolution and assembly of galaxies and their environments (2014, background): “This surface tension impedes the development of hydrodynamical instabilities resulting in poor mixing of gas phases, which could in principle compromise simulations of galaxy formation (e.g. Sijacki et al. 2012; Nelson et al. 2013).”
A unified multiwavelength model of galaxy formation (2015, background): “…results suffered from numerical inaccuracies, and that most of the gas forming galaxies does in fact get shock-heated to the halo virial temperature as it falls into halos, and then radiatively cools (Nelson et al. 2013), although this shock-heating may occur well within the virial radius.”
A characteristic scale for cold gas (2016, background): “…& Rees, 1978; Birnboim & Dekel, 2003; Maller & Bullock, 2004) and cosmological simulations (e. g. van de Voort et al., 2011; Fumagalli et al., 2014; Nelson et al., 2013; Fielding et al., 2016) consistently predict its presence, and stacked observations have directly detected virialized gas in…”
The Illustris simulation: the evolving population of black holes across cosmic time (2014, methodology): “Also, it has been shown (Bauer & Springel 2012; Vogelsberger et al. 2012) that in AREPO there is no heating of gas due to artificial dissipation of subsonic turbulence, as is the case in the standard SPH, which may affect cooling rates as well (Nelson et al. 2013).”
UNLEASHING POSITIVE FEEDBACK: LINKING THE RATES OF STAR FORMATION, SUPERMASSIVE BLACK HOLE ACCRETION, AND OUTFLOWS IN DISTANT GALAXIES (2013, background): “However, the rate of early cold accretion in massive galaxies may be severely overestimated according to more realistic, moving mesh hydrodynamic simulations (Nelson et al. 2013).”
Theoretical Challenges in Galaxy Formation (2016, background): “From numerical studies it is still unclear whether the gas is accreted onto the galaxies cold filaments (Dekel et al. 2009, Kereš et al. 2005) or whether the filaments dissolve in the halos and accretion is more smooth (Nelson et al. 2013).”