A5018199600- Cryospheric studies and observations
- Astronomy and Astrophysical Research
- Remote Sensing and Land Use
- X-ray Diffraction in Crystallography
- Stellar, planetary, and galactic studies
- Scientific Computing and Data Management
- Astrophysics and Star Formation Studies
- Galaxies: Formation, Evolution, Phenomena
- Calibration and Measurement Techniques
- Astrophysical Phenomena and Observations
- Climate change and permafrost
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Remote-Sensing Image Classification
- Distributed and Parallel Computing Systems
- Advanced Vision and Imaging
- Infrared Target Detection Methodologies
- Advanced Image and Video Retrieval Techniques
- Geochemistry and Geologic Mapping
- Research Data Management Practices
- Remote Sensing and LiDAR Applications
- Geological Studies and Exploration
- Pulsars and Gravitational Waves Research
- Geophysics and Gravity Measurements
- Atmospheric and Environmental Gas Dynamics
Urbana University
2024-2025
University of Illinois Urbana-Champaign
2015-2024
National Taiwan University
2023
National Center for Theoretical Sciences
2023
Toyota Technological Institute at Chicago
2022-2023
Royal Holloway University of London
2022
National Center for Supercomputing Applications
2014-2020
University of California, Santa Barbara
2006-2019
National Center for Supercomputing Applications
2010-2019
University of California System
2016-2018
The analysis of complex multiphysics astrophysical simulations presents a unique and rapidly growing set challenges: reproducibility, parallelization, vast increases in data size complexity chief among them. In order to meet these challenges, open up new avenues for collaboration between users multiple simulation platforms, we present yt (available at http://yt.enzotools.org/), an source, community-developed visualization toolkit. Analysis with are oriented around physically relevant...
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...
By definition, Population III stars are metal-free, and their protostellar collapse is driven by molecular hydrogen cooling in the gas phase, leading to large characteristic masses. II with lower masses form when star-forming reaches a critical metallicity of 10−6–10−3.5 Z☉. We present an adaptive mesh refinement radiation hydrodynamics simulation that follows transition from star formation. The maximum spatial resolution 1 comoving parsec allows for individual clouds be well resolved...
Starlight from galaxies plays a pivotal role throughout the process of cosmic reionisation. We present statistics dwarf galaxy properties at z > 7 in haloes with masses up to 10^9 solar masses, using cosmological radiation hydrodynamics simulation that follows their buildup starting Population III progenitors. find metal-enriched star formation is not restricted atomic cooling ($T_{\rm vir} \ge 10^4$ K) haloes, but can occur down ~10^6 especially neutral regions. Even though these smallest...
Previous high resolution cosmological simulations predict the first stars to appear in early universe be very massive and form isolation. Here we discuss a simulation which central 50 solar mass clump breaks up into two cores, having ratio of one, with one fragment collapsing densities 10^{-8} g/cc. The second fragment, at distance 800 astronomical units, is also optically thick its own cooling radiation from molecular hydrogen lines, but still able cool via collision-induced emission. dense...
We present the Grackle chemistry and cooling library for astrophysical simulations models. provides a treatment of non-equilibrium primordial H, D, He species, including H2 formation on dust grains; tabulated metal cooling; multiple UV background models; support radiation transfer arbitrary heat sources. The has an easily implementable interface simulation codes written in C, C++, Fortran as well Python with added convenience functions semi-analytical As open-source project, community...
We introduce the AGORA project, a comprehensive numerical study of well-resolved galaxies within LCDM cosmology. Cosmological hydrodynamic simulations with force resolutions ~100 proper pc or better will be run variety code platforms to follow hierarchical growth, star formation history, morphological transformation, and cycle baryons in out 8 halo masses M_vir ~= 1e10, 1e11, 1e12, 1e13 Msun at z=0 two different ("violent" "quiescent") assembly histories. The techniques implementations used...
The authors have developed a real-time, view-based gesture recognition system. Optical flow is estimated and segmented into motion blobs. Gestures are recognized using rule-based technique based on characteristics of the blobs such as relative size. Parameters (e.g., frequency) then context specific techniques. system has been applied to create an interactive environment for children.
Numerous cosmological hydrodynamic studies have addressed the formation of galaxies. Here we choose to study first stages galaxy formation, including non-equilibrium atomic primordial gas cooling, gravity and hydrodynamics. Using initial conditions appropriate for concordance model structure perform two adaptive mesh refinement simulations ~10^8 M_sun galaxies at high redshift. The calculations resolve Jeans length all times with more than 16 cells capture over 14 orders magnitude in scales....
We study the buildup of magnetic fields during formation Population III star-forming regions by conducting cosmological simulations from realistic initial conditions and varying Jeans resolution. To investigate this in detail, we start identical conditions, mandating 16, 32, 64 zones per length, variation their field amplification. find that, while compression results some amplification, turbulent velocity fluctuations driven collapse can further amplify an initially weak seed via dynamo...
The act of sharing scientific knowledge is rapidly evolving away from traditional articles and presentations to the delivery executable objects that integrate data computational details (e.g., scripts workflows) upon which findings rely. This envisioned coupling process essential advancing science but faces technical institutional barriers. Whole Tale project aims address these barriers by connecting computational, data-intensive research efforts with larger process—transforming discovery...
The viewing graph represents a set of views that are related by pairwise relative geometries. In the context Structure-from-Motion (SfM), is input to incremental or global estimation pipeline. Much effort has been put towards developing robust algorithms overcome potentially inaccurate geometries in during SfM. this paper, we take fundamentally different approach SfM and instead focus on improving quality before applying Our main contribution novel optimization improves enforcing loop...
Massive stars provide feedback that shapes the interstellar medium of galaxies at all redshifts and their resulting stellar populations. Here we present three adaptive mesh refinement radiation hydrodynamics simulations illustrate impact momentum transfer from ionising to absorbing gas on star formation in high-redshift dwarf galaxies. Momentum is calculated by solving radiative equation with a ray tracing algorithm spatial angular coordinates. We find input partially affects increasing...
Multi-scale models can facilitate whole plant simulations by linking gene networks, protein synthesis, metabolic pathways, physiology, and growth. Whole be further integrated with ecosystem, weather, climate to predict how various interactions respond environmental perturbations. These have the potential fill in missing mechanistic details generate new hypotheses prioritize directed engineering efforts. Outcomes will potentially accelerate improvement of crop yield, sustainability, increase...
Cosmological hydrodynamical simulations of galaxy evolution are increasingly able to produce realistic galaxies, but the largest hurdle remaining is in constructing subgrid models that accurately describe behavior stellar feedback.As an alternate way test and calibrate such models, we propose focus on circumgalactic medium.To do so, generate a suite adaptive-mesh refinement (AMR) for Milky-Way-massed run z = 0, systematically varying feedback implementation.We then post-process simulation...
article Free Access Share on Perceptual user interfaces (introduction) Authors: Matthew Turk Microsoft Research, Redmond, WA WAView Profile , George Robertson Authors Info & Claims Communications of the ACMVolume 43Issue 3March 2000 pp 32–34https://doi.org/10.1145/330534.330535Published:01 March 2000Publication History 139citation2,961DownloadsMetricsTotal Citations139Total Downloads2,961Last 12 Months220Last 6 weeks55 Get Citation AlertsNew Alert added!This alert has been successfully added...
Simulations of the formation Population III (Pop III) stars suggest that they were much more massive than Pop II and I observed today. This is due to collapse dynamics metal-free gas, which regulated by radiative cooling molecular hydrogen. We study how gas clouds altered addition metals star-forming environment performing a series simulations pre-enriched star at various metallicities. To make clean comparison with formation, we use initial conditions identical simulation, low ionization no...
The Dark Sky Simulations are an ongoing series of cosmological N-body simulations designed to provide a quantitative and accessible model the evolution large-scale Universe. Such models essential for many aspects study dark matter energy, since we lack sufficiently accurate analytic non-linear gravitational clustering. In July 2014, made available general community our early data release, consisting over 55 Terabytes simulation products, including largest date, which used $1.07 \times...
We present gamer-2, a GPU-accelerated adaptive mesh refinement (AMR) code for astrophysics. It provides rich set of features, including time-stepping, several hydrodynamic schemes, magnetohydrodynamics, self-gravity, particles, star formation, chemistry, and radiative processes with grackle, data analysis yt, memory pool efficient object allocation. gamer-2 is fully bitwise reproducible. For the performance optimization, it adopts hybrid OpenMP/MPI/GPU parallelization utilizes overlapping...
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
Cosmological shocks are a critical part of large-scale structure formation, and responsible for heating the intracluster medium in galaxy clusters. In addition, they capable accelerating non-thermal electrons protons. this work, we focus on acceleration at shock fronts, which is thought to be radio relics—extended features vicinity merging By combining high-resolution adaptive mesh refinement/N-body cosmological simulations with an accurate shock-finding algorithm model electron...
The transformation of atomic hydrogen to molecular through three-body reactions is a crucial stage in the collapse primordial, metal-free halos, where first generation stars (Population III stars) Universe are formed. However, published literature, rate coefficient for this reaction uncertain by nearly an order magnitude. We report on results both adaptive mesh refinement (AMR) and smoothed particle hydrodynamics (SPH) simulations halos as function value coefficient. For each simulation...