A5074032720- Computational Physics and Python Applications
- Galaxies: Formation, Evolution, Phenomena
- Meteorological Phenomena and Simulations
- Distributed and Parallel Computing Systems
- Geophysics and Gravity Measurements
- Cosmology and Gravitation Theories
- Astronomy and Astrophysical Research
- Dark Matter and Cosmic Phenomena
- Parallel Computing and Optimization Techniques
- Tropical and Extratropical Cyclones Research
- Scientific Computing and Data Management
- Stellar, planetary, and galactic studies
- Climate variability and models
- Astrophysics and Star Formation Studies
- Pulsars and Gravitational Waves Research
- Advanced Data Storage Technologies
- Scientific Research and Discoveries
- Precipitation Measurement and Analysis
- Gamma-ray bursts and supernovae
- Advanced Vision and Imaging
- Oceanographic and Atmospheric Processes
- Satellite Communication Systems
- Adaptive optics and wavefront sensing
- Hydrological Forecasting Using AI
Allen Institute for Artificial Intelligence
2022
Seattle University
2022
NOAA Geophysical Fluid Dynamics Laboratory
2020-2021
Vulcan (United States)
2020-2021
University of California, Irvine
2015-2018
The Feedback In Realistic Environments (FIRE) project explores feedback in cosmological galaxy formation simulations. Previous FIRE simulations used an identical source code (FIRE-1) for consistency. Motivated by the development of more accurate numerics - including hydrodynamic solvers, gravitational softening, and supernova coupling algorithms exploration new physics (e.g. magnetic fields), we introduce FIRE-2, updated numerical implementation GIZMO code. We run a suite compare against...
We investigate the effect of self-interacting dark matter (SIDM) on density profiles $V_{\rm max} \simeq 40~km~s^{-1}$ isolated dwarf halos -- scale relevance for too big to fail problem (TBTF) using very high-resolution cosmological zoom simulations. Each halo has millions particles within its virial radius. find that SIDM models with cross sections per unit mass spanning range σ/m = $0.5 - 50$ $cm^2~g^{-1}$ alleviate TBTF and produce constant cores size 300-1000 pc, comparable half-light...
We present a suite of 15 cosmological zoom-in simulations isolated dark matter halos, all with masses $M_{\rm halo} \approx 10^{10}\,{\rm M}_\odot$ at $z=0$, in order to understand the relationship between halo assembly, galaxy formation, and feedback's effects on central density structure dwarf galaxies. These are part Feedback Realistic Environments (FIRE) project performed extremely high resolution. The resultant galaxies have stellar that consistent rough abundance matching estimates,...
We present FIRE/Gizmo hydrodynamic zoom-in simulations of isolated dark matter halos, two each at the mass classical dwarf galaxies ($M_{\rm vir} \simeq 10^{10} M_{\odot}$) and ultra-faint 10^9 M_{\odot}$), with feedback implementations. The resultant central lie on an extrapolated abundance matching relation from $M_{\star} 10^6$ to $10^4 M_{\odot}$ without a break. Every host is filled subhalos, many which form stars. Our dwarfs 10^6 have 1-2 well-resolved satellites = 3-200 \times 10^3...
Abstract We present the System for High‐resolution prediction on Earth‐to‐Local Domains (SHiELD), an atmosphere model developed by Geophysical Fluid Dynamics Laboratory (GFDL) coupling nonhydrostatic FV3 Dynamical Core to a physics suite originally taken from Global Forecast System. SHiELD is designed demonstrate new capabilities within its components, explore applications, and answer scientific questions through these functionalities. A variety of configurations are presented, including...
We perform a systematic Bayesian analysis of rotation versus dispersion support (vrot/σ) in 40 dwarf galaxies throughout the local volume (LV) over stellar mass range |$10^{3.5} \rm \, M_{{\odot }}< M_{\rm \star }< 10^{8} }}$|. find that stars ∼80 per cent LV studied – both satellites and isolated systems are dispersion-supported. In particular, we show 6/10 dwarfs our sample have vrot/σ ≲ 1.0, while all 2.0. These results challenge traditional view gas-rich irregulars (dIrrs) distributed...
We compare a suite of four simulated dwarf galaxies formed in 1010 M☉ haloes collisionless cold dark matter (CDM) with the same an identical galaxy formation model but non-zero cross-section for DM self-interactions. These cosmological zoom-in simulations are part Feedback In Realistic Environments (fire) project and utilize fire-2 hydrodynamics physics. find stellar masses self-interacting (SIDM) σ/m = 1 cm2 g-1 very similar to those CDM (spanning M★ ≈ 105.7-7.0 M☉) all runs lie on...
We present an empirical approach for interpreting gravitational wave signals of binary black hole mergers under the assumption that underlying population is sourced by remnants stellar evolution. Using observed relationship between galaxy mass and metallicity, we predict count as a function mass. show, example, like Milky Way should host millions $\sim 30~M_\odot$ holes dwarf satellite galaxies Draco 100$ such remnants, with weak dependence on assumed IMF evolution model. Most low-mass...
We investigate the response of self-interacting dark matter (SIDM) halos to growth galaxy potentials using idealized simulations, each run in tandem with standard collisionless Cold Dark Matter (CDM). find a greater diversity SIDM halo profiles compared CDM profiles. If stellar gravitational potential strongly dominates central parts galaxy, then can be as dense on observable scales. For extreme cases highly compact disks core collapse occur, leading that are denser and cuspier than their...
We use a suite of high-resolution cosmological dwarf galaxy simulations to test the accuracy commonly-used mass estimators from Walker et al.(2009) and Wolf al.(2010), both which depend on observed line-of-sight velocity dispersion 2D half-light radius galaxy, $Re$. The are part Feedback in Realistic Environments (FIRE) project include twelve systems with stellar masses spanning $10^{5} - 10^{7} M_{\odot}$ that have structural kinematic properties similar those dispersion-supported dwarfs....
Abstract. Simulation software in geophysics is traditionally written Fortran or C++ due to the stringent performance requirements these codes have satisfy. As a result, researchers who use high-productivity languages for exploratory work often find hard understand, modify, and integrate with their analysis tools. fv3gfs-wrapper an open-source Python-wrapped version of NOAA (National Oceanic Atmospheric Administration) FV3GFS (Finite-Volume Cubed-Sphere Global Forecast System) global...
Earth system models are developed with a tight coupling to target hardware, often containing specialized code predicated on processor characteristics. This stems from using imperative languages that hard-code computation schedules and layout. We present detailed account of optimizing the Finite Volume Cubed-Sphere Dynamical Core (FV3), improving productivity performance. By declarative Python-embedded stencil domain-specific language data-centric optimization, we abstract hardware-specific...
We present the System for High-resolution prediction on Earth-to-Local Domains (SHiELD), an atmosphere model coupling nonhydrostatic FV3 Dynamical Core to a physics suite originally taken from Global Forecast System. SHiELD is designed demonstrate new capabilities within its components, explore applications, and answer scientific questions through these functionalities. A variety of configurations are presented, including short-to-medium-range subseasonal-to-seasonal (S2S) prediction,...
Abstract. Progress in leveraging current and emerging high-performance computing infrastructures using traditional weather climate models has been slow. This become known more broadly as the software productivity gap. With end of Moore's law driving forward rapid specialization hardware architectures, building simulation codes on a low-level language with hardware-specific optimizations is significant risk. As solution, we present Pace, an implementation nonhydrostatic FV3 dynamical core...
Earth system models are developed with a tight coupling to target hardware, often containing specialized code predicated on processor characteristics. This stems from using imperative languages that hard-code computation schedules and layout. We present detailed account of optimizing the Finite Volume Cubed-Sphere Dynamical Core (FV3), improving productivity performance. By declarative Python-embedded stencil domain-specific language data-centric optimization, we abstract hardware-specific...
Abstract. Progress in leveraging current and emerging high-performance computing infrastructures using traditional weather climate models has been slow. This become known more broadly as the software productivity gap. With end of Moore's Law driving forward rapid specialization hardware architectures, building simulation codes on a low-level language with specific optimizations is significant risk. As solution, we present Pace, an implementation nonhydrostatic FV3 dynamical core which...
We present the System for High-resolution prediction on Earth-to-Local Domains (SHiELD), an atmosphere model coupling nonhydrostatic FV3 Dynamical Core to a physics suite originally taken from Global Forecast System. SHiELD is designed demonstrate new capabilities within its components, explore applications, and answer scientific questions through these functionalities. A variety of configurations are presented, including short-to-medium-range subseasonal-to-seasonal (S2S) prediction,...
Earth and Space Science Open Archive This work has been accepted for publication in Journal of Advances Modeling Systems (JAMES). Version RecordESSOAr is a venue early communication or feedback before peer review. Data may be preliminary. Learn more about preprints. preprintOpen AccessYou are viewing an older version [v1]Go to new versionGFDL SHiELD: A Unified System Weather-to-Seasonal PredictionAuthors Lucas Harris iD Linjiong Zhou Shian-Jiann Lin Jan-Huey Chen Xi Kun Gao Matthew Morin...
Simulation software in geophysics is traditionally written Fortran or C++ due to the stringent performance requirements these codes have satisfy. As a result, are often hard understand, modify and interface with high-productivity languages used for exploratory work. \texttt{fv3gfs-wrapper} an open-source Python-wrapped version of NOAA's FV3GFS global atmospheric model, which coded Fortran. The wrapper provides simple interfaces progress main loop get set state from model. These enable wide...