A5051311828- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Black Holes and Theoretical Physics
- Geophysics and Gravity Measurements
- Geophysics and Sensor Technology
- Cosmology and Gravitation Theories
- Gamma-ray bursts and supernovae
- Particle Accelerators and Free-Electron Lasers
- Computational Fluid Dynamics and Aerodynamics
- Seismic Waves and Analysis
- Advanced Numerical Methods in Computational Mathematics
- Seismic Imaging and Inversion Techniques
- Magnetic confinement fusion research
- advanced mathematical theories
- Numerical methods for differential equations
- Quantum chaos and dynamical systems
- Fluid Dynamics and Turbulent Flows
- Relativity and Gravitational Theory
- Mathematical Biology Tumor Growth
- High-pressure geophysics and materials
- Computational Physics and Python Applications
- Nonlinear Waves and Solitons
- Adaptive optics and wavefront sensing
- Superconducting Materials and Applications
- Numerical methods in engineering
California Institute of Technology
2022-2025
Max Planck Institute for Gravitational Physics
2022-2023
The gravitational wave strain emitted by a perturbed black hole (BH) ringing down is typically modeled analytically using first-order BH perturbation theory. In this Letter, we show that second-order effects are necessary for modeling ringdowns from merger simulations. Focusing on the strain's (ℓ,m)=(4,4) angular harmonic, presence of quadratic effect across range binary mass ratios agrees with theoretical expectations. We find (4,4) mode's amplitude exhibits scaling fundamental (2,2)...
We present SEOBNRv5HM, a more accurate and faster inspiral-merger-ringdown gravitational waveform model for quasicircular, spinning, nonprecessing binary black holes within the effective-one-body (EOB) formalism. Compared to its predecessor, SEOBNRv4HM, (i) incorporates recent high-order post-Newtonian results in inspiral, with improved resummations, (ii) includes modes $(\ensuremath{\ell},|m|)=(3,2),(4,3)$, addition (2,2), (3,3), (2,1), (4,4), (5,5) already implemented (iii) is calibrated...
We investigate quadratic quasinormal mode coupling in black hole spacetime through numerical experiments of single perturbed holes using both relativity and second-order perturbation theory. Focusing on the dominant $\ensuremath{\ell}=|m|=2$ quadrupolar modes, we find good agreement (within $\ensuremath{\sim}10%$) between these approaches, with discrepancies attributed to truncation error uncertainties from fitting. Our results align earlier studies extracting coefficients select binary...
Quasi-normal mode (QNM) modeling is an invaluable tool for characterizing remnant black holes, studying strong gravity, and testing GR. Only recently have QNM studies begun to focus on multimode fitting numerical relativity (NR) strain waveforms. As GW observatories become even more sensitive they will be able resolve higher-order modes. Consequently, fits critically important, in turn require a thorough treatment of the asymptotic frame at $\mathscr{I}^+$. The first main result this work...
We propose two frequency-domain filters to analyze ringdown signals of binary black hole mergers. The first rational filter is constructed based on a set (arbitrary) quasi-normal modes (QNMs) the remnant holes, whereas second full comes from transmissivity holes. can remove corresponding QNMs original time-domain ringdowns, while changing early inspiral in trivial way - merely time and phase shift. After filtering out dominant QNMs, we visualize existence various subdominant effects. For...
We give full details regarding the new Cauchy-characteristic evolution (CCE) system in spectre. The implementation is built to provide streamlined flexibility for either extracting waveforms during process of a spectre binary compact object simulation or as stand-alone module from worldtube data provided by another code base. Using our recently presented improved analytic formulation, CCE free pure-gauge logarithms that would spoil spectral convergence scheme. It gracefully extracts all five...
The Bondi-van der Burg-Metzner-Sachs (BMS) group, which uniquely describes the symmetries of asymptotic infinity and therefore gravitational waves that propagate there, has become increasingly important for accurate modeling waveforms. In particular, waveform models, such as post-Newtonian (PN) expressions, numerical relativity (NR), black hole perturbation theory, produce results are in different BMS frames. Consequently, to build a model waveforms produced during merging compact objects,...
Numerical relativity simulations provide the most precise templates for gravitational waves produced by binary black hole mergers. However, many of these use an incomplete waveform extraction technique---extrapolation---that fails to capture important physics, such as memory effects. Cauchy-characteristic evolution (CCE), contrast, is a much more physically accurate procedure that fully evolves Einstein's equations future null infinity and accurately captures expected physics. In this work,...
One of the most promising avenues to perform numerical evolutions in theories beyond general relativity is approach, a proposal which new “driver” equations are added evolution way that allows for stable evolutions. In this direction, we extend code p evolve “fixed” version scalar Gauss-Bonnet theory decoupling limit, phenomenologically interesting hairy black hole solutions vacuum. We focus on isolated systems both with and without linear angular momentum, propose driver equation improve...
A fully relativistic three-dimensional Cauchy-characteristic matching (CCM) algorithm is implemented for physical degrees of freedom in a numerical relativity code spectre. The method free approximations and can be applied to any system. We test the with various scenarios involving smooth data, including propagation Teukolsky waves within flat background, perturbation Kerr black hole wave, injection gravitational-wave pulse from characteristic grid. Our investigations reveal no instabilities...
The ringdown portion of a binary black hole merger consists sum modes, each containing an infinite number tones that are exponentially damped sinusoids. In principle, these can be measured as gravitational-waves with observatories like LIGO/Virgo/KAGRA, however in practice it is unclear how many meaningfully resolved. We investigate the consistency and resolvability overtones quadrupolar $\ensuremath{\ell}=m=2$ mode by starting at late times when gravitational waveform expected to well...
Numerical-relativity surrogate models for both black-hole merger waveforms and remnants have emerged as important tools in gravitational-wave astronomy. While producing very accurate predictions, their applicability is limited to the region of parameter space where numerical-relativity simulations are available computationally feasible. Notably, this excludes extreme mass ratios. We present a machine-learning approach extend validity existing future toward test-particle limit, targeting...
We propose a new approach toward reconstructing the late-time near-horizon geometry of merging binary black holes, and computing gravitational-wave echoes from exotic compact objects. A black-hole merger spacetime can be divided by time-like hypersurface into Black-Hole Perturbation (BHP) region, in which space-time approximated homogeneous linear perturbations final Kerr hole, nonlinear region. At late times, boundary between two regions is an infalling shell. The BHP region contains...
Recent efforts to numerically simulate compact objects in alternative theories of gravity have largely focused on the time-evolution equations. Another critical aspect is construction constraint-satisfying initial data with precise control over properties systems under consideration. Here, we augment extended conformal thin sandwich framework construct quasistationary for black hole scalar Gauss-Bonnet theory and implement it open-source p code. Despite resulting elliptic system being...
Abstract Cauchy-characteristic evolution (CCE) is a powerful method for accurately extracting gravitational waves at future null infinity. In this work, we extend the previously implemented CCE system within numerical relativity code SpECTRE by incorporating scalar field. This allows to capture features of beyond-general-relativity theories. We derive contributions equations motion, Weyl computations, Bianchi identities, and balance laws Our algorithm, tested across various scenarios,...
Discontinuous Galerkin methods are popular because they can achieve high order where the solution is smooth, capture shocks while needing only nearest-neighbor communication, and relatively easy to formulate on complex meshes. We perform a detailed comparison of various limiting strategies presented in literature applied equations general relativistic magnetohydrodynamics. compare standard $\mathrm{minmod}/\mathrm{\ensuremath{\Lambda}}{\mathrm{\ensuremath{\Pi}}}^{N}$ limiter, hierarchical...
We investigate quadratic quasinormal mode coupling in black hole spacetime through numerical simulations of single perturbed holes using both relativity and second-order perturbation theory. Focusing on the dominant $\ell=|m|=2$ quadrupolar modes, we find good agreement (within $\sim10\%$) between these approaches, with discrepancies attributed to truncation error uncertainties from fitting. Our results align earlier studies extracting coefficients select binary merger simulations, showing...
Elliptic partial differential equations must be solved numerically for many problems in numerical relativity, such as initial data every simulation of merging black holes and neutron stars. Existing elliptic solvers can take multiple days to solve these at high resolution when matter is involved, because they are either hard parallelize or require a large amount computational resources. Here we present new solver linear nonlinear that designed scale with on computing clusters. To achieve...
Binary black hole simulations become increasingly more computationally expensive with smaller mass ratios, partly because of the longer evolution time, and lengthscale disparity dictates time steps. The program initiated by Dhesi et al. [Phys. Rev. D 104, 124002 (2021)] explores a method for alleviating scale in ratios intermediate astrophysical range (${10}^{\ensuremath{-}4}\ensuremath{\lesssim}q\ensuremath{\lesssim}{10}^{\ensuremath{-}2}$), where purely perturbative methods may not be...
Abstract We present a discontinuous Galerkin-finite difference hybrid scheme that allows high-order shock capturing with the Galerkin method for general relativistic magnetohydrodynamics in dynamical spacetimes. several optimizations and stability improvements to our algorithm allow successfully simulate single, rotating, binary neutron stars. The achieves efficiency of methods throughout almost entire spacetime during inspiral phase, while being able robustly capture shocks resolve stellar...
Abstract We present an adaptive-order positivity-preserving conservative finite-difference scheme that allows a high-order solution away from shocks and discontinuities while guaranteeing positivity robustness at discontinuities. This is achieved by monitoring the relative power in highest mode of reconstructed polynomial reducing order when series no longer converges. Our approach similar to multidimensional optimal detection strategy, but differs several ways. The priori so does not...