A5027900558- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Mechanics and Biomechanics Studies
- Geophysics and Gravity Measurements
- Geophysics and Sensor Technology
- Cosmology and Gravitation Theories
- Astrophysics and Cosmic Phenomena
- Neutrino Physics Research
- Astro and Planetary Science
- Magnetic confinement fusion research
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- High-pressure geophysics and materials
- Particle physics theoretical and experimental studies
- Seismic Waves and Analysis
- High-Energy Particle Collisions Research
- Relativity and Gravitational Theory
- Astronomical Observations and Instrumentation
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Adaptive optics and wavefront sensing
- Planetary Science and Exploration
- Dark Matter and Cosmic Phenomena
University of New Hampshire at Manchester
2018-2025
North Carolina State University
2024-2025
University of New Hampshire
2018-2024
University of California, Berkeley
2024
University of Tennessee at Knoxville
2024
Lawrence Berkeley National Laboratory
2015-2019
Columbia University
2017
Canadian Institute for Theoretical Astrophysics
2012-2016
University of Toronto
2012-2016
Cornell University
2008-2012
Extracting the unique information on ultradense nuclear matter from gravitational waves emitted by merging neutron-star binaries requires robust theoretical models of signal. We develop a novel effective-one-body waveform model that includes, for first time, dynamic (instead only adiabatic) tides neutron star as well merger signal neutron-star--black-hole binaries. demonstrate importance comparing our against new numerical-relativity simulations nonspinning spanning more than 24...
We investigate the long-term evolution of black hole accretion disks formed in neutron star mergers. These expel matter that contributes to an $r$-process kilonova, and can produce relativistic jets powering short gamma-ray bursts. Here we report results a three-dimensional, general-relativistic magnetohydrodynamic (GRMHD) simulation such disk which is evolved for long enough ($\sim 9$s, or $\sim 6\times 10^5 r_{\rm g}/c$) achieve completion mass ejection far from disk. Our model starts with...
Determining the final result of black-hole--neutron-star mergers, and, in particular, amount matter remaining outside black hole at late times and its properties, has been one main motivations behind numerical simulation these systems. Black-hole--neutron-star binaries are among most likely progenitors short gamma-ray bursts---as long as massive (probably a few percents solar mass), hot accretion disks formed around hole. Whether this actually happens strongly depends on physical...
Gravitational-wave (GW) and electromagnetic (EM) signals from the merger of a Neutron Star (NS) Black Hole (BH) are highly anticipated discovery in extreme gravity, nuclear-, astrophysics. We develop simple formula that distinguishes between outcomes predicts post-merger remnant mass, validated with 75 simulations. Our improves on existing results by describing critical unexplored regimes: comparable masses higher BH spins. These important to differentiate NSNS NSBH mergers, infer source...
Neutron star mergers are among the most promising sources of gravitational waves for advanced ground-based detectors. These also expected to power bright electromagnetic signals, in form short gamma-ray bursts, infrared/optical transients powered by r-process nucleosynthesis neutron-rich material ejected merger, and radio emission from interaction that ejecta with interstellar medium. Simulations these fully general relativistic codes critical understand merger postmerger wave signals their...
We investigate the nucleosynthesis of heavy elements in winds ejected by accretion disks formed neutron star mergers. compute element formation disk outflows from hypermassive (HMNS) remnants variable lifetime, including effect angular momentum transport evolution. employ long-term axisymmetric hydrodynamic simulations to model ejecta, and r-process with tracer particles using a nuclear reaction network containing $\sim 8000$ species. find that previously known strong correlation between...
This is an exciting time for the study of r-process nucleosynthesis. Recently, a neutron star merger GW170817 was observed in extraordinary detail with gravitational waves and electromagnetic radiation from radio to γ rays. The very red color associated kilonova suggests that mergers are important site. Astrophysical simulations core collapse supernovae making rapid progress. Detection both electron neutrinos antineutrinos next galactic supernova will constrain composition neutrino-driven...
Searches for electromagnetic counterparts of gravitational-wave signals have redoubled since the first detection in 2017 a binary neutron star merger with gamma-ray burst, optical/infrared kilonova, and panchromatic afterglow. Yet, one LIGO/Virgo observing run later, there has not yet been second, secure identification an counterpart. This is surprising given that localization uncertainties events LIGO Virgo's third run, O3, were much larger than predicted. We explain this by showing...
Providing an accurate modeling of neutrino physics in dense astrophysical environments such as binary neutron star mergers presents a challenge for hydrodynamic simulations. Nevertheless, understanding how flavor transformation can occur and affect the dynamics, mass ejection, nucleosynthesis will need to be achieved future. Computationally expensive, large-scale simulations frequently evolve first classical angular moments distributions. By promoting these quantities matrices space, we...
Abstract Multi-messenger astrophysics has produced a wealth of data with much more to come in the future. This enormous set will reveal new insights into physics core-collapse supernovae, neutron star mergers, and many other objects where it is actually possible, if not probable, that operation. To tease out different possibilities, we need analyze signals from photons, neutrinos, gravitational waves, chemical elements. task made all difficult when necessary evolve neutrino component...
Black-hole--neutron-star mergers resulting in the disruption of neutron star and formation an accretion disk and/or ejection unbound material are prime candidates for joint detection gravitational-wave electromagnetic signals when next generation detectors comes online. However, properties postmerger remnant very sensitive to parameters binary (mass ratio, black-hole spin, radius). In this paper, we study impact radius alignment spin on black-hole--neutron-star within range mass ratio...
We present a code for solving the coupled Einstein-hydrodynamics equations to evolve relativistic, self-gravitating fluids. The Einstein field are solved in generalized harmonic coordinates on one grid using pseudospectral methods, while fluids evolved another shock-capturing finite difference or volume techniques. show that accurately evolves equilibrium stars and accretion flows. Then we simulate an equal-mass nonspinning black hole-neutron star binary, evolving through final four orbits...
We present a first exploration of the results neutron star-black hole mergers using black masses in most likely range $7M_\odot-10M_\odot$, neutrino leakage scheme, and modeling star material through finite-temperature nuclear-theory based equation state. In spins which is tidally disrupted ($\chi_{\rm BH}\gtrsim 0.7$), we show that merger consistently produces large amounts cool ($T\lesssim 1\,{\rm MeV}$), unbound, neutron-rich ($M_{\rm ej}\sim 0.05M_\odot-0.20M_\odot$). A comparable amount...
We present a first simulation of the post-merger evolution black hole-neutron star binary in full general relativity using an energy-integrated relativistic truncated moment formalism for neutrino transport. describe our implementation and important tests code, before studying formation phase disk after merger. use as initial data existing merger neutron 1.4 solar mass with hole 7 dimensionless spin a/M=0.8. Comparing simpler leakage scheme treatment neutrinos, we find noticeable differences...
Recent observations have shown that in many exoplanetary systems the spin axis of parent star is misaligned with planet's orbital axis. These been used to argue against scenario short-period planets migrated their present-day locations due tidal interactions natal discs. However, this interpretation based on assumption spins young stars are parallel rotation axes protostellar discs around them. We show interaction between a magnetic and its circumstellar disc can (but not always) effect...
Compact binary mergers involving at least one neutron star are important sources of gravitational waves. To fully describe such mergers, however, requires not only general relativity but also nuclear physics, hydrodynamics, and neutrino transport. The paper by Foucart et al. marks a significant step in this direction showing the sensitivity observables to energy spectrum.
There is irresistible observational evidence that binary systems of compact objects with at least one neutron star are progenitors short gamma-ray bursts, as well a production site for r-process elements, when some matter ejected by the merger and an accretion disk formed. The recent observations gravitational waves in conjunction electromagnetic counterparts fuel need models predicting outcome given properties associated outflows function initial parameters binary. In this manuscript, we...
Neutron star mergers are unique laboratories of accretion, ejection, and r-process nucleosynthesis. We used 3D general relativistic magnetohydrodynamic simulations to study the role post-merger magnetic geometry in evolution merger remnant discs around stationary Kerr black holes. Our fully capture mass jet production, owing their exceptionally long duration exceeding $4$ s. Poloidal field configurations produce jets with energies $E_\mathrm{jet} \sim (4{-}30)\times10^{50}$ erg, isotropic...
The spin of black holes in hole-neutron star (BHNS) binaries can have a strong influence on the merger dynamics and postmerger state; wide variety magnitudes orientations are expected to occur nature. In this paper, we report first simulations full general relativity BHNS mergers with misaligned hole spin. We vary magnitude from a/m=0 a/m=0.9 for aligned cases, misalignment angle 0 80 degrees a/m=0.5. restrict our study 3:1 mass ratio systems use simple Gamma-law equation state. find that...
On 2019 August 14, the Advanced LIGO and Virgo interferometers detected high-significance gravitational wave (GW) signal S190814bv. The GW data indicated that event resulted from a neutron star--black hole (NSBH) merger, or potentially low-mass binary black merger. Due to low false alarm rate precise localization (23 deg$^2$ at 90\%), S190814bv presented community with best opportunity yet directly observe an optical/near-infrared counterpart NSBH To search for potential counterparts, GROWTH...
GW170817 showed that neutron star mergers not only emit gravitational waves but also can release electromagnetic signatures in multiple wavelengths. Within the first half of third observing run Advanced LIGO and Virgo detectors, there have been a number wave candidates compact binary systems for which at least one component is potentially star. In this article, we look S190425z, S190426c, S190510g, S190901ap, S190910h, predicted to non-zero remnant mass, more detail. All these triggers...
After the discovery of gravitational waves from binary black holes (BBHs) and neutron stars (BNSs) with LIGO Virgo detectors, neutron-star (NSBHs) are natural next class systems to be observed. In this work, we develop a waveform model for aligned-spin NSBHs combining BBH baseline (available in effective-one-body approach) phenomenological description tidal effects (extracted numerical-relativity simulations) correcting amplitude during late inspiral, merger ringdown account NS disruption....