Present Members

  • Matthew Duez
    Principle Investigator

  • Nishad Muhammed PhD student
    Research: Nishad invstigated the stability properties of hypermassive neutron stars of the sort formed by binary neutron star mergers. He first created equilibrium configurations, slightly perturbed them, and then evolved them using short 2D SpEC simulations to see if they oscillate or collapse. His latest project is to study energy release from the annihilation of neutrinos and antineutrinos emitted by the accretion disks around black holes formed by compact binary mergers and failed supernovea.
    Papers:
    • Stability of hypermassive neutron stars with realistic rotation and entropy profiles by Muhammed et al, submitted to Physical Review D, arXiv:2403.05642
    • High angular momentum hot differentially rotating equilibrium star evolutions in conformally flat spacetime by Cheong et al, submitted to Physical Review D, arXiv:2402.18529
  • Pavan Chawhan PhD student
    Research: Pavan is working to extend binary neutron star simulations using 2D SpEC to study post-merger evolution, similarly to how Milad did for a black hole-neutron star post-merger (see below), but now with the added complication of evolving the spacetime metric. Part of this project is to consider different models of angular momentum transport inside the central remnant, which attempt to capture the effects of various MHD instabilities.
    Papers:
    • Stability of hypermassive neutron stars with realistic rotation and entropy profiles by Muhammed et al, submitted to Physical Review D, arXiv:2403.05642
    • High angular momentum hot differentially rotating equilibrium star evolutions in conformally flat spacetime by Cheong et al, submitted to Physical Review D, arXiv:2402.18529
  • Amlan Nanda PhD student
    Research: Amlan is going to use SpEC to study compact binaries which include boson stars. Right now, we are creating initial data. He will also be working with Sukanta Bose on a project studying the effects of dynamical tides in binary neutron star gravitational waveforms.

Past Members

  • Marlo Morales Degree: Masters 2024
    Research: Marlo investigated outer boundary conditions to the Einstein field equations, in particular working on implementations of a high-order boundary condition that removes reflections of gravitational waves.
    Papers:
    • Numerical Relativity Multimodal Waveforms using Absorbing Boundary Conditions by Buchman et al, submitted to Classical and Quantum Gravity, arXiv:2402.12544
  • Courtney Cadenhead
    Degreee: Masters 2022
    Research: As an undergraduate, Courtney studied electromagnetic energy fluxes in SpEC simulations. As a masters degree student, she investigated dynamo action in the black hole accretion disks we simulate, in particular the question of how to model 3D magnetorotational turbulence in axisymmetry in a covariant and well-motivated way.
    Papers:
    • Axisymmetric Hydrodynamics in Numerical Relativity Using a Multipatch Method by Jesse et al, Classical and Quantum Gravity 37 23501 (2020), arXiv:2005.01848
    • Analysis of Dynamo Effects in a Relativistic, Cartesian Global Accretion Disk Simulation: Toward Global Models by Duez et al, in prep.
  • Milad Haddadi
    Degree: PhD 2020
    Research: Milad used 2D simulations to continue SpEC simulations for the first time for multiple seconds after merger, long enough to study the late-time disk evolution and outflows.
    Papers:
    • Late-time post-merger modeling of a compact binary: effects of relativity, r-process heating, and treatment of transport effects by Haddadi et al, Class. Quantum Grav. 40 085008 (2023) arXiv:2208.02367
    • A comparison of momentum transport models for numerical relativity by Duez et al, Phys. Rev. D 102, 104050 (2020), arXiv:2008.05019
    • Axisymmetric Hydrodynamics in Numerical Relativity Using a Multipatch Method by Jesse et al, Classical and Quantum Gravity 37 23501 (2020), arXiv:2005.01848
    • Evolution of the Magnetized, Neutrino-Cooled Accretion Disk in the Aftermath of a Black Hole Neutron Star Binary Merger by Nouri et al, Phys. Rev. D 97, 083014 (2018), arXiv:1710.07423
  • Jerred Jesse
    Degree: PhD 2020 Research: Jerred developed a way to implement axisymmetry in multipatch codes and studied hydrodynamics, magnetohydrodynamics, and neutrino radiation transport in 2D numerical relativity.
    Papers:
    - Late-time post-merger modeling of a compact binary: effects of relativity, r-process heating, and treatment of transport effects by Haddadi et al, Class. Quantum Grav. 40 085008 (2023) arXiv:2208.02367
    • A comparison of momentum transport models for numerical relativity by Duez et al, Phys. Rev. D 102, 104050 (2020), arXiv:2008.05019
    • Axisymmetric Hydrodynamics in Numerical Relativity Using a Multipatch Method by Jesse et al, Classical and Quantum Gravity 37 23501 (2020), arXiv:2005.01848
    • Elastic Scattering in General Relativistic Ray Tracing for Neutrinos by Deaton et al, Phys. Rev. D 98, 103014 (2018), arXiv:1806.10255
  • Jesus Caro
    Degree: MS thesis 2018 Research: Jesus carried out black hole-neutron star merger simulations to assess the reliability of waveform templates available to LIGO when used to ascertain neutron star properties.
    Papers:
    • Gravitational waveforms from SpEC simulations : neutron star-neutron star and low-mass black hole-neutron star binaries by Foucart et al, Phys. Rev. D 99, 044008 (2019), arXiv:1812.06988
    • Systematic effects from black hole-neutron star waveform model uncertainties on the neutron star equation of state by Chakravarti et al, Phys. Rev. D 99, 024049 (2019), arXiv:1809.04349
    • Black hole-neutron star mergers using a survey of finite-temperature equations of state by Brege et al, Phys. Rev. D 98, 063009 (2018), arXiv:1804.09823
  • Wyatt Brege
    Degree: PhD 2017
    Research: Wyatt carried out a survey of black hole-neutron star simulations with different nuclear-theory based, finite-temperature equations of state, looking for signatures of the equation of state on the merger dynamics and immediate post-merger state.
    Papers:
    • Systematic effects from black hole-neutron star waveform model uncertainties on the neutron star equation of state by Chakravarti et al, Phys. Rev. D 99, 024049 (2019), arXiv:1809.04349
    • Black hole-neutron star mergers using a survey of finite-temperature equations of state by Brege et al, Phys. Rev. D 98, 063009 (2018), arXiv:1804.09823
    • Dynamical ejecta from precessing neutron star-black hole mergers with a hot, nuclear-theory based equation of state by Foucart et al, Classical and Quantum Gravity, 34, 4 (2017), arXiv:1611.01159
  • Fatemeh Nouri
    Degree: PhD 2016
    Research: Fatemeh simulated the effect of magnetic fields on neutrino-cooled post-merger disks, developing an innovative study of the thermal evolution. She has continued to work with the WSU group as a postdoc, studying tidal excitation of neutron star modes in binaries.
    Papers:
    • Nonlinear mode-tide coupling in coalescing binary neutron stars with relativistic corrections by Nouri et al, under review, arXiv:2107.13339
    • Evolution of the Magnetized, Neutrino-Cooled Accretion Disk in the Aftermath of a Black Hole Neutron Star Binary Merger by Nouri et al, Phys. Rev. D 97, 083014 (2018), arXiv:1710.07423
    • Magnetic effects on the low-T/W instability in differentially rotating neutron stars by Muhlberger et al, Phys. Rev. D 90, 104014 (2014), arXiv:1405.2144

  • Veronica Ruiz
    Degree: MS non-thesis 2015
    Research: Veronica worked on black hole-neutron star simulations to study tidal effects on the waveforms.

  • Michael Brett Deaton
    Degree: PhD 2015
    Research: Brett carried out the first numerical relativity simulations of black hole-neutron star mergers to include realistic microphysics, including neutrino cooling. The techniques he developed for evolutions and analysis of outflows continued to be used in subsequent papers. The work he began at WSU on studying distributions of neutrinos from binary mergers using ray tracing was completed and published during his postdoc.
    Papers:
    • Elastic Scattering in General Relativistic Ray Tracing for Neutrinos by Deaton et al, Phys. Rev. D 98, 103014 (2018), arXiv:1806.10255
    • Black hole-neutron star mergers using a survey of finite-temperature equations of state by Brege et al, Phys. Rev. D 98, 063009 (2018), arXiv:1804.09823
    • Evolution of the Magnetized, Neutrino-Cooled Accretion Disk in the Aftermath of a Black Hole Neutron Star Binary Merger by Nouri et al, Phys. Rev. D 97, 083014 (2018), arXiv:1710.07423
    • Neutron star-black hole mergers with a nuclear equation of state and neutrino cooling: Dependence in the binary parameters by Foucart et al, Phys. Rev. D 90, 024026 (2014), arXiv:1405.1121
    • Black Hole-Neutron Star Mergers with a Hot Nuclear Equation of State: Outflow and Neutrino-Cooled Disk for a Low-Mass, High-Spin Case by Deaton et al, Astrophys. J. 776, 47 (2013), arXiv:1304.3384
    • Black hole-neutron star mergers at realistic mass ratios: Equation of state and spin orientation effects by Foucart et al, Phys. Rev. D 87, 084006 (2013), arXiv:1212.4810