A5088005039- Galaxies: Formation, Evolution, Phenomena
- Solar and Space Plasma Dynamics
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Traffic Prediction and Management Techniques
- Traffic control and management
- Cosmology and Gravitation Theories
- Transportation Planning and Optimization
- Astrophysical Phenomena and Observations
- Cellular Automata and Applications
- Geomagnetism and Paleomagnetism Studies
- Ionosphere and magnetosphere dynamics
- DNA and Biological Computing
- Scientific Research and Discoveries
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Computational Physics and Python Applications
- Geophysics and Gravity Measurements
- Algorithms and Data Compression
- Particle accelerators and beam dynamics
- Black Holes and Theoretical Physics
- Modular Robots and Swarm Intelligence
University of California, San Diego
2009-2019
Poughkeepsie Public Library District
2018
IBM (United States)
2017
South China University of Technology
2016
San Diego Supercomputer Center
2016
Los Alamos National Laboratory
2008-2013
Tianjin University
2013
University of Copenhagen
2011
University of Hong Kong
2001-2003
This paper describes the open-source code Enzo, which uses block-structured adaptive mesh refinement to provide high spatial and temporal resolution for modeling astrophysical fluid flows. The is Cartesian, can be run in one, two, three dimensions, supports a wide variety of physics including hydrodynamics, ideal non-ideal magnetohydrodynamics, N-body dynamics (and, more broadly, self-gravity fluids particles), primordial gas chemistry, optically thin radiative cooling metal-enriched plasmas...
In this paper, we present the first results from Renaissance Simulations, a suite of extremely high-resolution and physics-rich AMR calculations high-redshift galaxy formation performed on Blue Waters supercomputer. These simulations contain hundreds well-resolved galaxies at , make several novel, testable predictions. Most critically, show that ultraviolet luminosity function our simulated is consistent with observations high-z populations bright end but lower luminosities essentially flat...
We examine the effects of self-gravity and magnetic fields on supersonic turbulence in isothermal molecular clouds with high resolution simulations adaptive mesh refinement. These use large root grids (512^3) to capture four levels refinement density, for an effective 8,196^3. Three Mach 9 are performed, two super-Alfv\'enic one trans-Alfv\'enic. find that gravity splits into populations, low density turbulent state collapsing state. The exhibits properties similar non-self-gravitating this...
Many astrophysical applications involve magnetized turbulent flows with shock waves. Ab initio star formation simulations require a robust representation of supersonic turbulence in molecular clouds on wide range scales imposing stringent demands the quality numerical algorithms. We employ super-Alfvénic decay as benchmark test problem to assess and compare performance nine popular MHD methods actively used model formation. The set codes includes: ENZO, FLASH, KT-MHD, LL-MHD, PLUTO, PPML,...
Non-thermal radio emission from cosmic-ray electrons in the vicinity of merging galaxy clusters is an important tracer cluster merger activity, and result complex physical processes that involve magnetic fields, particle acceleration, gas dynamics, radiation. In particular, objects known as relics are thought to be shock-accelerated that, when embedded a field, emit synchrotron radiation wavelengths. order properly model this emission, we utilize adaptive mesh refinement simulation...
Cosmic reionization is thought to be primarily fueled by the first generations of galaxies. We examine their stellar and gaseous properties, focusing on star formation rates escape ionizing photons, as a function halo mass, redshift, environment using full suite {\it Renaissance Simulations} with an eye provide better inputs global simulations. This suite, carried out adaptive mesh refinement code Enzo, unprecedented in terms size physical ingredients. The simulations probe overdense,...
We report the results of first self-consistent three-dimensional adaptive mesh refinement magnetohydrodynamical simulations Population III star formation including Biermann battery effect. find that stellar cores formed this effect are both qualitatively and quantitatively similar to those from hydrodynamics-only (non-MHD) cosmological simulations. observe peak magnetic fields ≃ 10−9 G in center our star-forming halo at z 17.55 a baryon density nB ∼ 1010 cm−3. The created by predominantly...
In this work, we present EnzoMHD, the extension of cosmological code Enzo to include effects magnetic fields through ideal magnetohydrodynamics approximation. We use a higher order Godunov method for computation interface fluxes. two constrained transport methods compute electric field from those fluxes, which simultaneously advances induction equation and maintains divergence field. A second-order divergence-free reconstruction technique is used interpolate in block-structured adaptive mesh...
Recent simulations of Population III star formation have suggested that some fraction form in binary systems, addition to having a characteristic mass tens solar masses. The deaths metal-free stars result the initial chemical enrichment universe and production first stellar-mass black holes. Here we present cosmological adaptive mesh refinement simulation an overdense region forms few 109 M☉ dark matter halos over 13,000 by redshift 15. We find most do not until they reach Mvir ∼ 107 because...
Enzo (Enzo Developers, 2019a) is a block-structured adaptive mesh refinement code that widely used to simulate astrophysical fluid flows (primarily, but not exclusively, cosmological structure formation, star and turbulence).The community project with dozens of users, has contributed hundreds peer-reviewed publications in astrophysics, physics, computer science.The utilizes Cartesian can be run one, two, or
We present self-consistent cosmological magnetohydrodynamic (MHD) simulations that simultaneously follow the formation of a galaxy cluster and magnetic field ejection by an active galactic nucleus (AGN). find fields ejected AGNs, though initially distributed in relatively small volumes, can be transported throughout further amplified intra-cluster medium (ICM) turbulence during process. The ICM is shown to generated sustained frequent mergers smaller halos. Furthermore, cluster-wide dynamo...
Due to their long mean free path, X-rays are expected have an important impact on cosmic reionization by heating and ionizing the intergalactic medium (IGM) large scales, especially after simulations suggested that Population III (Pop III) stars may form in pairs at redshifts as high 20–30. We use Pop distribution evolution from a self-consistent cosmological radiation hydrodynamic simulation of formation first galaxies simple X-ray binary model estimate output high-density region larger...
Theory and simulations suggest that magnetic fields from radio jets lobes powered by their central super massive black holes can be an important source of in the galaxy clusters. This is paper II a series studies where we present self-consistent high-resolution adaptive mesh refinement cosmological magnetohydrodynamic (MHD) simultaneously follow formation cluster evolution ejected active galactic nucleus (AGN). We studied 12 different clusters with virial masses ranging 1 $\times$ 10$^{14}$...
The existence of supermassive black holes as early z ~ 7 is one the great unsolved problems in cosmological structure formation. One leading theory argues that they are born during catastrophic baryon collapse 15 protogalaxies strong Lyman-Werner UV backgrounds. Atomic line cooling such galaxies fragments baryons into massive clumps thought to directly 10^4 - 10^5 solar-mass holes. We have now discovered some these can instead become stars eventually explode pair-instability supernovae with...
We present results on the formation of Pop III stars at redshift 7.6 from Renaissance Simulations, a suite extremely high-resolution and physics-rich radiation transport hydrodynamics cosmological adaptive-mesh refinement simulations high galaxy performed Blue Waters supercomputer. In survey volume about 220 comoving Mpc$^3$, we found 14 galaxies with recent star formation. The surprisingly late is possible due to two factors: (i) metal enrichment process local slow, leaving plenty pristine...
The first galaxies in the universe are building blocks of all observed galaxies. We present scaling relations for forming at redshifts z ⩾ 15 when reionization is just beginning. utilize "Rarepeak" cosmological radiation hydrodynamics simulation that captures complete star formation history over 3300 galaxies, starting with massive Population III stars form dark matter halos as small ∼106 M☉. make various correlations between bulk halo quantities, such virial, gas, and stellar masses...
We present a series of cosmological magnetohydrodynamic (MHD) simulations that simultaneously follow the formation galaxy cluster and evolution magnetic fields ejected by an Active Galactic Nucleus (AGN). Specifically, we investigate influence both epoch AGN (z $\sim$ 3-0.5) energy ($\sim$ 3 $\times$ 10$^{57}$ - 2 10$^{60}$ ergs)on final field distribution in relatively massive (M$_{vir}$ $\sim$10$^{15}$ M$_\odot$). find as long are before major mergers history, can be transported throughout...
In this work, we present the mass and magnetic distributions found in a recent adaptive mesh refinement magnetohydrodynamic simulation of supersonic, super-Alfvénic, self-gravitating turbulence. Power-law tails are both density field probability functions, with P(ρ) ∝ ρ−1.6 P(B) B−2.7. A power-law relationship is also between strength density, B ρ0.5, throughout collapsing gas. The distribution gravitationally bound cores shown to be excellent agreement observation prestellar cores....
Context. Synchrotron radio halos at the center of merging galaxy clusters provide most spectacular and direct evidence presence relativistic particles magnetic fields associated with intracluster medium. The study polarized emission from has been shown to be extremely important constrain properties fields. However, detecting this signal is a very hard task current facilities.
We present synthetic observations for the first generations of galaxies in Universe and make predictions future deep field redshifts greater than 6. Due to strong impact nebular emission lines relatively compact scale HII regions, high resolution cosmological simulations a robust suite analysis tools are required properly simulate spectra. created software pipeline consisting FSPS, Hyperion, Cloudy our own generate IR from fully three-dimensional arrangement gas, dust, stars. Our...
Radio observations of galaxy clusters show that there are $\mu$G magnetic fields permeating the intra-cluster medium (ICM), but it is hard to accurately constrain strength and structure without help advanced computer simulations. We present qualitative comparisons synthetic VLA simulated radio Faraday Rotation Measure (RM) halos. The cluster formation modeled using adaptive mesh refinement (AMR) magneto-hydrodynamic (MHD) simulations with assumption initial injected into ICM by active...
Due to their long mean free paths, X-rays are expected have many significant impacts globally on the properties of intergalactic medium (IGM) by heating and ionizing processes large scales. At high redshifts, from Population (Pop) III binaries might important effects cosmic reionization Lyman alpha forest. As a continuation our previous work Pop binary (Xu et al. 2014), we use distribution evolution Renaissance Simulations, suite self-consistent cosmological radiation hydrodynamics...
Cosmological MHD simulations of galaxy cluster formation show a significant amplification seed magnetic fields. We developed novel method to decompose magnetized turbulence into modes and showed that the fraction fast mode is fairly large, around 1/4 in terms energy. This larger than was estimated before, which implies interacts with cosmic rays rather efficiently. propose framework deal electron proton reacceleration clusters includes feedback on turbulence. In particular, we establish new...