scholarly journals On the accretion history of galaxy clusters: temporal and spatial distribution

2020 ◽  
Vol 499 (2) ◽  
pp. 2303-2318
Author(s):  
David Vallés-Pérez ◽  
Susana Planelles ◽  
Vicent Quilis
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Adaptive Mesh Refinement ◽  
Adaptive Mesh ◽  
Temporal And Spatial Distribution ◽  
Mass Growth ◽  
Accretion Flows ◽  
Novel Approach ◽  
Mass Assembly ◽  
Gas Accretion

ABSTRACT We analyse the results of an Eulerian adaptive mesh refinement cosmological simulation in order to quantify the mass growth of galaxy clusters, exploring the differences between dark matter and baryons. We have determined the mass assembly histories (MAHs) of each of the mass components and computed several proxies for the instantaneous mass accretion rate (MAR). The mass growth of both components is clearly dominated by the contribution of major mergers, but high MARs can also occur during smooth accretion periods. We explored the correlations between MARs, merger events, and clusters’ environments, finding the mean densities in 1 ≤ r/R200m ≤ 1.5 to correlate strongly with Γ200m in massive clusters that undergo major mergers through their MAH. From the study of the dark matter velocity profiles, we find a strong anticorrelation between the MAR proxies Γ200m and α200m. Last, we present a novel approach to study the angularly resolved distribution of gas accretion flows in simulations, which allows to extract and interpret the main contributions to the accretion picture and to assess systematic differences between the thermodynamical properties of each of these contributions using multipolar analysis. We have preliminarily applied the method to the best numerically resolved cluster in our simulation. Amongst the most remarkable results, we find that the gas infalling through the cosmic filaments has systematically lower entropy compared to the isotropic component, but we do not find a clear distinction in temperature.

scholarly journals Cosmic magnetic fields with masclet: an application to galaxy clusters

2020 ◽  
Vol 494 (2) ◽  
pp. 2706-2717
Author(s):  
Vicent Quilis ◽  
José-María Martí ◽  
Susana Planelles
Keyword(s):  
Magnetic Field ◽  
Galaxy Clusters ◽  
Adaptive Mesh Refinement ◽  
Adaptive Mesh ◽  
Pure Compression ◽  
Ideal Magnetohydrodynamics ◽  
Relative Errors ◽  
Cluster Values ◽  
The Magnetic Field ◽  
The Ideal

ABSTRACT We describe and test a new version of the adaptive mesh refinement cosmological code masclet. The new version of the code includes all the ingredients of its previous version plus a description of the evolution of the magnetic field under the approximation of the ideal magnetohydrodynamics (MHD). To preserve the divergence-free condition of MHD, the original divergence cleaning algorithm of Dedner et al. (2002) is implemented. We present a set of well-known 1D and 2D tests, such as several shock tube problems, the fast rotor, and the Orszag–Tang vortex. The performance of the code in all the tests is excellent with estimated median relative errors of ∇ · B in the 2D tests smaller than 5 × 10−5 for the fast rotor test, and 5 × 10−3 for the Orszag–Tang vortex. As an astrophysical application of the code, we present a simulation of a cosmological box of 40 comoving Mpc side length in which a primordial uniform comoving magnetic field of strength 0.1 nG is seeded. The simulation shows how the magnetic field is channelled along the filaments of gas and is concentrated and amplified within galaxy clusters. Comparison with the values expected from pure compression reveals an additional amplification of the magnetic field caused by turbulence in the central region of the cluster. Values of the order of ∼1µG are obtained in clusters at z ∼ 0 with median relative errors of ∇ · B below 0.4 per cent. The implications of a proper description of the dynamics of the magnetic field and their possible observational counterparts in future facilities are discussed.

scholarly journals Vector modes in ΛCDM: the gravitomagnetic potential in dark matter haloes from relativistic N-body simulations

2021 ◽  
Author(s):  
Cristian Barrera-Hinojosa ◽  
Baojiu Li ◽  
Marco Bruni ◽  
Jian-hua He
Keyword(s):  
Dark Matter ◽  
Adaptive Mesh Refinement ◽  
Gravitational Force ◽  
Percent Level ◽  
Adaptive Mesh ◽  
Velocity Fields ◽  
The Core ◽  
Transverse Modes ◽  
General Relativistic ◽  
The Impact

Abstract We investigate the transverse modes of the gravitational and velocity fields in ΛCDM, based on a high-resolution simulation performed using the adaptive-mesh refinement general-relativistic N-body code gramses. We study the generation of vorticity in the dark matter velocity field at low redshift, providing fits to the shape and evolution of its power spectrum over a range of scales. By analysing the gravitomagnetic vector potential, which is absent in Newtonian simulations, in dark matter haloes with masses ranging from ∼1012.5 h−1M⊙ to ∼1015 h−1M⊙, we find that its magnitude correlates with the halo mass, peaking in the inner regions. Nevertheless, on average, its ratio against the scalar gravitational potential remains fairly constant, below percent level, decreasing roughly linearly with redshift and showing a weak dependence on halo mass. Furthermore, we show that the gravitomagnetic acceleration in haloes peaks towards the core and reaches almost 10−10  h cm/s2 in the most massive halo of the simulation. However, regardless of the halo mass, the ratio between the gravitomagnetic force and the standard gravitational force is typically at around the 10−5 level inside the haloes, again without significant radius dependence. This result confirms that the gravitomagnetic effects have negligible impact on structure formation, even for the most massive structures, although its behaviour in low density regions remains to be explored. Likewise, the impact on observations remains to be understood in the future.

scholarly journals Phantom of RAMSES (POR): A new Milgromian dynamics N-body code

2015 ◽  
Vol 93 (2) ◽  
pp. 232-241 ◽  
Author(s):  
Fabian Lüghausen ◽  
Benoit Famaey ◽  
Pavel Kroupa
Keyword(s):  
Dark Matter ◽  
Dynamical Systems ◽  
Spatial Resolution ◽  
Gas Dynamics ◽  
Adaptive Mesh Refinement ◽  
High Spatial Resolution ◽  
Large Range ◽  
Adaptive Mesh ◽  
Scaling Relations ◽  
Disk Galaxies

Since its first formulation in 1983, Milgromian dynamics (MOND) has been very successful in predicting the gravitational potential of galaxies from the distribution of baryons alone, including general scaling relations and detailed rotation curves of large statistical samples of individual galaxies covering a large range of masses and sizes. Most predictions, however, rely on static models, and only a handful of N-body codes have been developed over the years to investigate the consequences of the Milgromian framework for the dynamics of complex evolving dynamical systems. In this work, we present a new Milgromian N-body code, which is a customized version of the RAMSES code (R. Teyssier. Astron. Astrophys. 385, 337 (2002). doi:10.1051/0004-6361:20011817 ) and thus comes with all its features: it includes particles and gas dynamics, and importantly allows for high spatial resolution of complex systems owing to the adaptive mesh refinement technique. It further allows the direct comparison between Milgromian simulations and standard Newtonian simulations with dark matter particles. We provide basic tests of this customized code and demonstrate its performance by presenting N-body computations of dark-matter-free spherical equilibrium models as well as dark-matter-free disk galaxies in Milgromian dynamics.

Pop III Supernova Feedback on the Formation of the First Galaxies

2019 ◽  
Vol 15 (S341) ◽  
pp. 253-256 ◽  
Author(s):  
Li-Hsin Chen ◽  
Ke-Jung Chen
Keyword(s):  
Dark Matter ◽  
Star Formation ◽  
Adaptive Mesh Refinement ◽  
Initial Conditions ◽  
Adaptive Mesh ◽  
Building Blocks ◽  
Dark Matter Halos ◽  
First Stars ◽  
Stellar Feedback ◽  
First Galaxies

AbstractModern cosmological simulations suggest that the hierarchical assembly of dark matter halos provided the gravitational wells that allowed the primordial gases to form stars and galaxies inside them. The first galaxies comprised of the first systems of stars gravitationally bound in dark matter halos are naturally recognized as the building blocks of early Universe. To understand the formation of the first galaxies, we use an adaptive mesh refinement (AMR) cosmological code, Enzo to simulate the formation and evolution of the first galaxies. We first model an isolated galaxy by considering much microphysics such as star formation, stellar feedback, and primordial gas cooling. To examine the effect of Pop III stellar feedback to the first galaxy formation, we adjust the initial temperature, density distribution and metallicity distributions by assuming different IMFs of the first stars. Our results suggest that star formation in the first galaxies is sensitive to the initial conditions of Pop III supernovae and their remnants. Our study can help to correlate the populations of the first stars and supernovae to star formation inside these first galaxies which may be soon observed by the (James Webb Space Telescope JWST).

scholarly journals Turbulent motions and shocks waves in galaxy clusters simulated with adaptive mesh refinement

2009 ◽  
Vol 504 (1) ◽  
pp. 33-43 ◽  
Author(s):  
F. Vazza ◽  
G. Brunetti ◽  
A. Kritsuk ◽  
R. Wagner ◽  
C. Gheller ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Adaptive Mesh Refinement ◽  
Mesh Refinement ◽  
Adaptive Mesh

scholarly journals Simulations of recoiling black holes: adaptive mesh refinement and radiative transfer

2017 ◽  
Vol 598 ◽  
pp. A38 ◽  
Author(s):  
Zakaria Meliani ◽  
Yosuke Mizuno ◽  
Hector Olivares ◽  
Oliver Porth ◽  
Luciano Rezzolla ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Radiative Transfer ◽  
Neutron Stars ◽  
Adaptive Mesh Refinement ◽  
Mesh Refinement ◽  
Adaptive Mesh ◽  
Numerical Code ◽  
Accretion Flows ◽  
General Relativistic

Context. In many astrophysical phenomena, and especially in those that involve the high-energy regimes that always accompany the astronomical phenomenology of black holes and neutron stars, physical conditions that are achieved are extreme in terms of speeds, temperatures, and gravitational fields. In such relativistic regimes, numerical calculations are the only tool to accurately model the dynamics of the flows and the transport of radiation in the accreting matter. Aims. We here continue our effort of modelling the behaviour of matter when it orbits or is accreted onto a generic black hole by developing a new numerical code that employs advanced techniques geared towards solving the equations of general-relativistic hydrodynamics. Methods. More specifically, the new code employs a number of high-resolution shock-capturing Riemann solvers and reconstruction algorithms, exploiting the enhanced accuracy and the reduced computational cost of adaptive mesh-refinement (AMR) techniques. In addition, the code makes use of sophisticated ray-tracing libraries that, coupled with general-relativistic radiation-transfer calculations, allow us to accurately compute the electromagnetic emissions from such accretion flows. Results. We validate the new code by presenting an extensive series of stationary accretion flows either in spherical or axial symmetry that are performed either in two or three spatial dimensions. In addition, we consider the highly nonlinear scenario of a recoiling black hole produced in the merger of a supermassive black-hole binary interacting with the surrounding circumbinary disc. In this way, we can present for the first time ray-traced images of the shocked fluid and the light curve resulting from consistent general-relativistic radiation-transport calculations from this process. Conclusions. The work presented here lays the ground for the development of a generic computational infrastructure employing AMR techniques to accurately and self-consistently calculate general-relativistic accretion flows onto compact objects. In addition to the accurate handling of the matter, we provide a self-consistent electromagnetic emission from these scenarios by solving the associated radiative-transfer problem. While magnetic fields are currently excluded from our analysis, the tools presented here can have a number of applications to study accretion flows onto black holes or neutron stars.

scholarly journals Troubled cosmic flows: turbulence, enstrophy, and helicity from the assembly history of the intracluster medium

2021 ◽  
Vol 504 (1) ◽  
pp. 510-527
Author(s):  
David Vallés-Pérez ◽  
Susana Planelles ◽  
Vicent Quilis
Keyword(s):  
Galaxy Clusters ◽  
Adaptive Mesh Refinement ◽  
Mesh Refinement ◽  
Adaptive Mesh ◽  
Main Process ◽  
Intracluster Medium ◽  
External Shocks ◽  
Large Samples ◽  
Formation History ◽  
History Of

ABSTRACT Both simulations and observations have shown that turbulence is a pervasive phenomenon in cosmic scenarios, yet it is particularly difficult to model numerically due to its intrinsically multiscale character which demands high resolutions. Additionally, turbulence is tightly connected to the dynamical state and the formation history of galaxies and galaxy clusters, producing a diverse phenomenology which requires large samples of such structures to attain robust conclusions. In this work, we use an adaptive mesh refinement (AMR) cosmological simulation to explore the generation and dissipation of turbulence in galaxy clusters, in connection to its assembly history. We find that major mergers, and more generally accretion of gas, is the main process driving turbulence in the intracluster medium. We have especially focused on solenoidal turbulence, which can be quantified through enstrophy. Our results seem to confirm a scenario for its generation which involves baroclinicity and compression at the external (accretion) and internal (merger) shocks, followed by vortex stretching downstream of them. We have also looked at the infall of mass to the cluster beyond its virial boundary, finding that gas follows trajectories with some degree of helicity, as it has already developed some vorticity in the external shocks.

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