Year: 2024
Type: article
Abstract: To fully unlock the scientific potential of upcoming gravitational wave (GW) interferometers, numerical relativity (NR) simulation accuracy will need to be greatly enhanced. We present three infrastructure-agnostic improvements to the moving-puncture approach for binary black hole (BBH) simulations, aimed at greatly reducing constraint violation and improving GW predictions. Although these improvements were developed within the highly efficient NR code blackholes@home, we demonstrate their effectiveness in the widely adopted einstein toolkit/carpet adaptive mesh refinement framework. Our improvements include a modified Kreiss-Oliger dissipation prescription, a Hamiltonian constraint damping adjustment to the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) equations, and an extra term to the $1+\mathrm{log}$ lapse evolution equation that slows the development of the sharp lapse feature, which dominates numerical errors in BBH simulations. With minimal increase in computational cost, these improvements greatly reduce GW noise, enabling the extraction of high-order GW modes previously obscured by numerical noise. They also improve convergence properties near and inside the convergent regime, reduce Hamiltonian (momentum) constraint violations in the strong-field region by roughly 2 (3) orders of magnitude, and in the GW-extraction zone by 5 (2) orders of magnitude. To promote community adoption, we have open-sourced the improved einstein toolkit thorn baikalvacuum used in this work. Although our focus is on BBH evolutions and the BSSN formulation, these improvements may also benefit compact binary simulations involving matter and other formulations, a focus for future investigations.
Author: Zachariah B. Etienne
Institutions: West Virginia University, University of Idaho
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1187630603, G127156130, G2778756634, G2873784832, THE RECENT OBSERVATIONS OF A BINARY NEUTRON STAR MERGER USING BOTH GRAVITATIONAL WAVE INTERFEROMETERS AS WELL AS ELECTROMAGNETIC TELESCOPES ACROSS THE FULL SPECTRUM HAVE INITIATED THE AGE OF MULTIMESSENGER ASTRONOMY AND ASTROPHYSICS. OUR PROPOSED NETWORK COMPRISING EXPERTS IN THE FIELDS OF THEORETICAL AND COMPUTATIONAL ASTROPHYSICS IS POISED TO COMPLEMENT THESE OBSERVATIONAL SUCCESSES WITH THE MOST THOROUGH AND COMPLETE EFFORT IN THE FIELD TO SIMULATE BINARY NEUTRON STAR COALESCENCES FROM PRIOR TO MERGER THROUGH TO THE FORMATION OF DISKS AND/OR COLLAPSE OF THE MERGED REMNANT THE PRODUCTION OF JETS AND LAUNCHING OF OUTFLOWS. BRINGING TOGETHER MORE THAN 15 RESEARCHERS SPREAD ACROSS FOUR NETWORK NODES (RIT JOHNS HOPKINS GODDARD SPACE FLIGHT CENTER AND WEST VIRGINIA UNIVERSITY) OUR WORK WILL YIELD HIGHLY ACCURATE PREDICTIONS OF GRAVITATIONAL WAVE SIGNATURES MULTI-WAVELENGTH ELECTROMAGNETIC AND NEUTRINO EMISSION AND NUCLEAR PROCESSING. THIS WORK IS CRITICAL FOR LINKING THE WEALTH OF OBSERVATIONAL DATA WE EXPECT ABOUT BINARY MERGERS CONTAINING NEUTRON STARS IN THE VERY NEAR FUTURE TO THE PHYSICAL PROCESSES GOVERNING THESE MERGERS. FOR THIS WORK WE WILL LEVERAGE OUR INDIVIDUAL AND COLLECTIVE EXPERTISE WITH SEVERAL CODES THAT STAND AT THE CUTTING-EDGE WITHIN THEIR FIELDS: ILLINOISGRMHD A THREE-DIMENSIONAL NUMERICAL RELATIVISTIC MAGNETOHYDRODYNAMICS (MHD) CODE PROVEN TO BE ABLE TO GENERATE MAGNETIZED JETS IN BINARY MERGERS; HARM3D A HIGHLY SCALABLE GENERAL-RELATIVISTIC MHD CODE CAPABLE OF USING FLEXIBLE COORDINATE SYSTEMS AND ARBITRARY SPACETIMES TO SIMULATE REMNANTS AND DISKS WITH UNPRECEDENTED PRECISION; PATCHWORK A BRAND-NEW MULTIPATCH INFRASTRUCTURE PERMITTING EFFICIENT AND ACCURATE SIMULATION OF FLUID SYSTEMS HETEROGENEOUS IN TERMS OF LOCAL PHYSICS SYMMETRIES LENGTH SCALES AND PREFERRED REFERENCE FRAMES; PANDURATA A NEUTRINO TRANSPORT CODE THAT CAN COUPLE TO MHD SIMULATIONS IN FULLY DYNAMICAL SPACETIMES; AND LORENE THE LEADING CODE FOR GENERATING RELATIVISTIC INITIAL DATA FOR BINARIES CONTAINING NEUTRON STARS. BY COUPLING THESE CODES TOGETHER WE WILL BE ABLE TO EVOLVE BINARY MERGER SIMULATIONS FOR LONGER TIMES AT HIGHER ACCURACIES WITH MORE ACCURATE PHYSICAL PREDICTIONS THAN ANY SINGLE CODE COULD ACCOMPLISH ON ITS OWN. OUR NETWORK WILL SIMULATE SEVERAL DIFFERENT PHYSICAL MODELS WHOSE PROPERTIES ARE CRITICAL TO UNDERSTAND IN ORDER TO INTERPRET FUTURE MULTIMESSENGER OBSERVATIONS. THESE INCLUDE BINARIES WHOSE MERGER LEADS TO A PROMPT COLLAPSE OF THE REMNANT TO A BLACK HOLE THOSE FOR WHICH THE COLLAPSE OCCURS AFTER A DELAY AND THOSE FOR WHICH WE EXPECT THE MERGER REMNANT TO PERSIST INDEFINITELY. IN EACH CASE WE WILL CALCULATE DETAILED ELECTROMAGNETIC AND NEUTRINO FLUXES AS WELL AS CHARACTERIZING THE EVOLUTION OF THE MAGNETIC FIELDS INCLUDING THE LAUNCHING OF JETS AND OTHER OUTFLOWS FROM THE NASCENT REMNANT. WE WILL ALSO SIMULATE BLACK HOLE-NEUTRON STAR MERGERS ALLOWING US TO DISENTANGLE THE TWO LEADING SOURCES OF MULTIMESSENGER TRANSIENTS BASED ON THEIR OBSERVED PROPERTIES. WE WILL ALSO PERFORM ``EVENTBASED'' SIMULATIONS USING PARAMETERS INFORMED BY SPECIFIC LIGO/VIRGO DETECTIONS AND THEREBY PERMITTING MUCH CLOSER COMPARISON WITH OBSERVABLES. THIS WORK IS CLEARLY RELEVANT TO NASA MISSIONS LIKE FERMI SWIFT CHANDRA HUBBLE AND SPITZER AND TO JWST ONCE IT COMES ONLINE. IT DIRECTLY ADDRESSES STRATEGIC PLAN OBJECTIVE 1.6: `` DISCOVER HOW THE UNIVERSE WORKS EXPLORE HOW IT BEGAN AND EVOLVED AND SEARCH FOR LIFE ON PLANETS AROUND OTHER STARS" AND TO THE CORE THEME OF NASA'S PHYSICS OF THE COSMOS PROGRAM WHOSE GOAL IS TO ``PROBE THE ORIGIN AND DESTINY OF OUR UNIVERSE INCLUDING THE NATURE OF BLACK HOLES DARK ENERGY DARK MATTER AND GRAVITY''., Collaborative Research: WoU-MMA: Toward Binary Neutron Star Mergers on a Moving-mesh, G3987227970, Boosting Algorithmic Efficiency: Numerical Relativity in Dynamical, Curvilinear Coordinates, THE L3 LASER INTERFEROMETER SPACE ANTENNA (LISA" AN ESA-NASA COLLABORATIVE MISSION) MAY PROVIDE OUR RST DETECTIONS OF GRAVITATIONAL WAVES (GWS) FROM MASSIVE BINARY BLACK HOLES (MBBHS). UNLIKE STELLAR-MASS BINARY BLACK HOLES OBSERVED BY LIGO/VIRGO MBBHS ARE THOUGHT TO INTERACT WITH THE SURROUNDING PLASMA AND GENERATE POTENTIALLY DETECTABLE ELECTROMAGNETIC (EM) EMISSION IN COINCIDENCE WITH THE GWS. A COINCIDENT GW AND EM DETECTION FROM MBBHS MAY YIELD UNPRECEDENTED INSIGHTS INTO HOW BLACK HOLES FORM AND IMPACT THEIR ENVIRONMENTS. HOWEVER UNLESS A CONSISTENT THEORETICAL FRAMEWORK CAN BE BUILT CONNECTING OBSERVED EM AND GW SIGNALS TO THE UNDERLYING PHYSICAL PROCESSES GENERATING THEM THE SCIENCE PRODUCT FROM SUCH HARD-FOUGHT OBSERVATIONS MAY BE TRAGICALLY UNDERWHELMING. SUCH A THEORETICAL FRAMEWORK DOES NOT YET EXIST. WHILE IT IS POSSIBLE TO SEPARATELY MODEL PLASMA OWS AND EM PARTICLE (PHOTON) MOTION NEAR BLACK HOLES WITH TWO SEPARATE PIECES OF SOFTWARE A SELF-CONSISTENT MODEL INCORPORATING PHOTON{PLASMA INTERACTIONS WOULD REQUIRE THAT THE TWO PIECES OF SOFTWARE BE MERGED INTO ONE. WEST VIRGINIA UNIVERSITY SUBCONTRACT PI Z. ETIENNE IS A COMPUTATIONAL ASTROPHYSICIST WHO AUTHORED AND MAINTAINS ILLINOISGRMHD A SUPERCOMPUTER-GRADE PIECE OF SOFTWARE CAPABLE OF FULLY GENERAL RELATIVISTIC COMPUTATIONAL MODELING OF MAGNETIZED PLASMA OWS AROUND BLACK HOLES. J. SCHNITTMAN AT NASA GSFC AUTHORED AND MAINTAINS PANDURATA SOFTWARE THAT TRACKS PHOTONS IN BLACK HOLE SPACETIMES. THIS PROPOSAL PROVIDES FUNDING THAT WILL ENABLE ETIENNE TO CONTINUE HIS WORK WITH SCHNITTMAN TO MERGE ILLINOISGRMHD AND PANDURATA INTO A PIECE OF SOFTWARE CAPABLE OF MODELING PHOTON{PLASMA INTERACTIONS IN A FULLY SELF-CONSISTENT WAY AND IN CONTINUED COLLABORATION WITH GSFC ASTROPHYSICISTS J. BAKER AND B. KELLY PRODUCE THE RST SELF-CONSISTENT THEORETICAL PREDICTIONS OF COINCIDENT GW AND EM SIGNALS FROM MBBH MERGERS. WE ADOPT A SYSTEMATIC APPROACH WHEREBY STATE-OF-THE-ART THEORETICAL PREDICTIONS CAN BE PRODUCED WHILE THE SOFTWARE MERGER IS IN PROGRESS., G6293982872, G6757593912, Collaborative Research: Frameworks: The Einstein Toolkit ecosystem: Enabling fundamental research in the era of multi-messenger astrophysics
OpenAlex ID: W4402515341