A5035099411- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Neutrino Physics Research
- Magnetic confinement fusion research
- High-Energy Particle Collisions Research
- Cosmology and Gravitation Theories
- High-pressure geophysics and materials
- Astro and Planetary Science
- Land Use and Ecosystem Services
- Particle accelerators and beam dynamics
- Computational Fluid Dynamics and Aerodynamics
- Geophysics and Sensor Technology
- Particle physics theoretical and experimental studies
- Fluid Dynamics and Turbulent Flows
- Nuclear physics research studies
- Planetary Science and Exploration
- Solar and Space Plasma Dynamics
- Astronomical Observations and Instrumentation
- Radio Astronomy Observations and Technology
- Seismic Waves and Analysis
- Gas Dynamics and Kinetic Theory
- Meteorological Phenomena and Simulations
Pennsylvania State University
2019-2025
Friedrich Schiller University Jena
2023
Princeton University
2017-2020
Institute for Advanced Study
2017-2020
University of California, Berkeley
2019
Los Alamos National Laboratory
2018
Lawrence Livermore National Laboratory
2018
Albert Einstein College of Medicine
2018
California Institute of Technology
2013-2016
Max Planck Institute for Gravitational Physics
2010-2014
Abstract Gravitational waves detected from the binary neutron star (NS) merger GW170817 constrained NS equation of state by placing an upper bound on certain parameters, describing binary’s tidal interactions. We show that interpretation UV/optical/infrared counterpart with kilonova models, combined new numerical-relativity results, imply a complementary lower deformability parameter. The joint constraints tentatively rule out both extremely stiff and soft equations state.
Abstract We present a systematic numerical relativity study of the mass ejection and associated electromagnetic transients nucleosynthesis from binary neutron star (NS) mergers. find that few 10 −3 M ⊙ material is ejected dynamically during The amount properties these outflows depend on parameters NS equation state (EOS). A small fraction ejecta, typically ∼10 −6 , accelerated by shocks formed shortly after merger to velocities larger than 0.6 c produces bright radio flares timescales weeks,...
We present fully general-relativistic simulations of binary neutron star mergers with a temperature and composition dependent nuclear equation state. study the dynamical mass ejection from both quasi-circular dynamical-capture eccentric mergers. systematically vary level our treatment microphysics to isolate effects neutrino cooling heating we compute nucleosynthetic yields ejecta. find that binaries can eject significantly more material than generate bright infrared radio emission. In all...
We present TEOBResumS, a new effective-one-body (EOB) waveform model for nonprecessing (spin-aligned) and tidally interacting compact binaries.Spin-orbit spin-spin effects are blended together by making use of the concept centrifugal EOB radius. The point-mass sector through merger ringdown is informed numerical relativity (NR) simulations binary black holes (BBH) computed with SpEC BAM codes. An improved, NR-based phenomenological description postmerger developed.The tidal TEOBResumS...
The detection of a kilo/macronova electromagnetic counterpart (AT2017gfo) the first gravitational wave signal compatible with merger two neutron stars (GW170817) has confirmed occurrence r-process nucleosynthesis in this kind events. blue and red components AT2017gfo have been interpreted as signature multi-component ejecta dynamics. However, explanation terms properties ejection mechanisms is still incomplete. In work, we analyse new semi-analytic model inferred from general relativistic...
We have conducted nineteen state-of-the-art 3D core-collapse supernova simulations spanning a broad range of progenitor masses. This is the largest collection sophisticated ever performed. found that while majority these models explode, not all do, and even in middle available mass may be less explodable. does mean those for which we did witness explosion would explode Nature, but they are prone to than others. One consequence "compactness" measure metric explodability. find lower-mass...
We study the gravitational wave signal from eight new 3D core-collapse supernova simulations. show that is dominated by $f$- and $g$-mode oscillations of protoneutron star its frequency evolution encodes contraction rate latter, which, in turn, known to depend on star's mass, equation state, transport properties warm nuclear matter. A lower-frequency component signal, associated with standing accretion shock instability, found only one our models. Finally, we energy radiated waves...
Abstract This paper describes the design and implementation of our new multigroup, multidimensional radiation hydrodynamics code F ornax provides a suite tests to validate its application in wide range physical regimes. Instead focusing exclusively on neutrino relevant core-collapse supernova problem for which is primarily intended, we present here classical rigorous demonstrations performance broad hydrodynamic multigroup problems. Our solves comoving-frame moment equations using M 1...
We present a systematic numerical-relativity study of the dynamical ejecta, winds and nucleosynthesis in neutron star merger remnants. Binaries with chirp mass compatible GW170817, different ratios, five microphysical equations state (EOS) are simulated an approximate neutrino transport subgrid model for magnetohydrodynamics turbulence up to 100 milliseconds postmerger. Spiral density waves propagating from remnant disk trigger wind flux ${\sim}0.1{-}0.5\,{\rm M_\odot/s}$ persisting entire...
ABSTRACT We present a new moment-based energy-integrated neutrino transport code for neutron star merger simulations in general relativity. In the context, ours is first to include Doppler effects at all orders υ/c, retaining non-linear neutrino–matter coupling terms. The validated with stringent series of tests. show that inclusion full terms necessary correctly capture trapping neutrinos relativistically moving media, such as differentially rotating remnants. perform preliminary proving...
ABSTRACT We present a systematic numerical relativity study of the impact different physics input and grid resolution in binary neutron star mergers. compare simulations employing neutrino leakage scheme, plus M0 M1 transport pure hydrodynamics. Additionally, we examine effect sub-grid scheme for turbulent viscosity. find that overall dynamics thermodynamics remnant core are robust, implying maximum density could be inferred from gravitational wave observations. Black hole collapse instead...
We study out-of-thermodynamic-equilibrium effects in neutron-star mergers with 3D general-relativistic neutrino-radiation large-eddy simulations. During mergers, the cores of neutron stars remain cold (T∼ a few MeV) and out thermodynamic equilibrium trapped neutrinos originating from hot collisional interface between stars. However, within ∼2 to 3 ms matter reach everywhere remnant massive star. Our results show that dissipative effects, such as bulk viscosity, if present, are only active...
We study initially unbound systems of two black holes using numerical relativity (NR) simulations performed with GR-Athena++. focus on regions the parameter space close to transition from scatterings dynamical captures, considering equal mass and spin-aligned configurations, as well unequal nonspinning ones. The results are then used validate effective-one-body (EOB) model TEOBResumS-Dal\'i for captures scatterings. find good agreement waveform phenomenologies, scattering angles, mismatches,...
Abstract We present the first seconds-long 2D general relativistic neutrino magnetohydrodynamic simulations of accretion-induced collapse (AIC) in rapidly rotating, strongly magnetized white dwarfs (WDs), which might originate as remnants double-WD mergers. This study examines extreme combinations magnetic fields and rotation rates, motivated both by need to address limitations axisymmetric explore physics AIC under rare conditions that, while yet be observationally confirmed, may consistent...
Abstract We introduce an extension to the AthenaK code for general-relativistic magnetohydrodynamics (GRMHD) in dynamical spacetimes using a 3+1 conservative Eulerian formulation. Like fixed-spacetime GRMHD solver, we use standard finite-volume methods evolve fluid and constrained-transport scheme preserve divergence-free constraint magnetic field. also utilize first-order flux correction (FOFC) reduce need artificial atmosphere optionally enforce maximum principle improve robustness....
We present THC: a new high-order flux-vector-splitting code for Newtonian and special-relativistic hydrodynamics designed direct numerical simulations of turbulent flows. Our implements variety different reconstruction algorithms, such as the popular weighted essentially non oscillatory monotonicity-preserving schemes, or more specialised bandwidth-optimised WENO scheme that has been specifically study compressible turbulence. show first systematic comparison these schemes in physics well In...
Despite the recent rapid progress in numerical relativity, a convergence order less than second has so far plagued codes solving Einstein-Euler system of equations. We report simulations inspiral binary neutron stars quasi-circular orbits computed with new code employing high-order, high-resolution shock-capturing, finite-differencing schemes that, for first time, go beyond second-order barrier. In particular, without any tuning or alignment, we measure above three both phase and amplitude...
In this paper, we present the results of our three-dimensional, multi-group, multi-neutrino-species radiation/hydrodynamic simulation using state-of-the-art code F{\sc{ornax}} terminal dynamics core a non-rotating 16-M$_{\odot}$ stellar progenitor. The calculation incorporates redistribution by inelastic scattering, correction for effect many-body interactions on neutrino-nucleon scattering rates, approximate general relativity (including effects gravitational redshifts), velocity-dependent...
Abstract We present Chandra and Very Large Array observations of GW170817 at ∼521–743 days post-merger, a homogeneous analysis the entire data set. find that late-time nonthermal emission follows expected evolution an off-axis relativistic jet, with steep temporal decay <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>F</mml:mi> </mml:mrow> <mml:mi>ν</mml:mi> </mml:msub> <mml:mo>∝</mml:mo> <mml:msup> <mml:mi>t</mml:mi>...
Massive neutron star (NS) with lifetimes of at least several seconds are expected to be the result a sizable fraction NS mergers. We study their formation using large set numerical relativity simulations. show that they initially endowed angular momentum significantly exceeds mass-shedding limit for rigidly-rotating equilibria. find gravitational-wave (GW) emission is not able remove this excess within time over which solid body rotation should achieved. Instead, we argue could carried away...
Using the new state-of-the-art core-collapse supernova (CCSN) code F{\sc{ornax}}, we have simulated three-dimensional dynamical evolution of cores 9-, 10-, 11-, 12-, and 13-M$_{\odot}$ stars from onset collapse. Stars 8-M$_{\odot}$ to constitute roughly 50% all massive stars, so explosive potential for this mass range is important overall theory CCSNe. We find that 12-M$_{\odot}$ models explode in 3D easily, but model does not. From these findings, fact slightly more progenitors seem...
With the first observation of a binary neutron star merger through gravitational waves and light GW170817, compact mergers have now taken center stage in nuclear astrophysics. They are thought to be one main astrophysical sites production r-process elements, observations become fundamental tool constrain properties matter. Here, we review our current understanding dynamics mergers, general, GW170817 particular. We discuss physical processes governing inspiral, merger, postmerger evolution,...