Fast extreme-mass-ratio-inspiral waveforms: New tools for millihertz gravitational-wave data analysis
Year: 2021
Type: article
Abstract: We present the fastemriwaveforms (FEW) package, a collection of tools to build and analyze extreme mass ratio inspiral (EMRI) waveforms. Here, we expand on [A. J. K. Chua et al., Phys. Rev. Lett. 126, 051102 (2021).] that introduced the first fast and accurate fully-relativistic EMRI waveform template model. We discuss the construction of the overall framework; constituent modules; and the general methods used to accelerate EMRI waveforms. Because the fully relativistic FEW model waveforms are for now limited to eccentric orbits in the Schwarzschild spacetime, we also introduce an improved augmented analytic kludge (AAK) model that describes generic Kerr inspirals. Both waveform models can be accelerated using graphics processing unit (GPU) hardware. With the GPU-accelerated waveforms in hand, a variety of studies are performed including an analysis of EMRI mode content, template mismatch, and fully Bayesian Markov Chain Monte Carlo-based EMRI parameter estimation. We find relativistic EMRI waveform templates can be generated with fewer harmonic modes ($\ensuremath{\sim}10--100$) without biasing signal extraction. However, we show for the first time that extraction of a relativistic injection with semirelativistic amplitudes can lead to strong bias and anomalous structure in the posterior distribution for certain regions of parameter space.
Authors: Michael L. Katz, Alvin J. K. Chua, Lorenzo Speri, Niels Warburton, Scott A. Hughes
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Awards: G1662313980, Accurate waveforms for extreme- and intermediate-mass-ratio inspirals, ONE OF THE MOST IMPORTANT ANTICIPATED SOURCES FOR THE LOW-FREQUENCY SPACE-BASED GRAVITATIONAL-WAVE (GW) ANTENNA LISA ARE THE INSPIRALS OF STELLAR MASS COMPACT BODIES INTO MASSIVE BLACK HOLES. IN SUCH BINARIES THE SMALLER MEMBER SPENDS MANY TENS OF THOUSANDS OF ORBITS DEEP IN THE LARGER BLACK HOLE'S STRONG FIELD. AS SUCH GWS FROM THESE "EXTREME MASS RATIO INSPIRALS" (OR "EMRIS") CARRY A CLEAN MAP OF THE LARGE BLACK HOLE'S SPACETIME. PRELIMINARY ANALYSES SHOW THAT THESE SOURCES WILL MAKE POSSIBLE EXQUISITELY PRECISE MEASUREMENTS OF MASSIVE BLACK HOLE PROPERTIES MEASURING BLACK HOLE DEMOGRAPHICS TO REDSHIFT Z OF ABOUT 0.5 - 1 AND ENABLING PRECISE CONSISTENCY TESTS OF STRONG-FIELD GRAVITY NEAR BLACK HOLE EVENT HORIZONS. SUCH MEASUREMENTS WILL RELY HEAVILY ON THEORETICAL MODELING. EMRI WAVEFORMS WILL HAVE AMPLITUDES A FACTOR TEN OR MORE SMALLER THAN NOISE SO DETECTING AND MEASURING THEIR WAVES WILL REQUIRE MODELS THAT CAN TRACK EMRI WAVES' PHASE OVER THE TENS OF THOUSANDS OF ORBITS THAT THEY RADIATE IN THE BAND OF LISA. THEORETICAL EFFORTS OVER THE PAST DECADE HAVE DONE MUCH TO CLARIFY HOW WELL LISA CAN MEASURE THESE WAVES AND WHAT CAN BE LEARNED FROM GW MEASUREMENTS. MOST OF THE COMMUNITY'S EFFORTS ARE PRESENTLY FOCUSED ON SELF FORCE CALCULATIONS COMPUTING EFFECTS ARISING FROM THE COMPACT BODY'S INTERACTION WITH ITS OWN DEFORMATION TO THE SPACETIME. HOW FAR MUST SUCH ANALYSES BE PUSHED BEFORE WE ARE CONFIDENT WE HAVE MODELED ALL OBSERVATIONALLY SIGNIFICANT EFFECTS? IS SECOND ORDER IN THE SMALL BODY'S MASS RATIO "FAR ENOUGH"? WHAT OTHER EFFECTS MUST BE INCLUDED IN ORDER FOR EMRI MEASUREMENTS TO ACHIEVE THEIR PROMISE? DO WE NEED TO INCLUDE THE INFLUENCE OF THE SMALLER BODY'S SPIN OR ITS QUADRUPOLE MOMENT? CAN A THIRD BODY IN THE NEIGHBORHOOD OF THE EMRI AFFECT THE SYSTEM AT A SIGNIFICANT LEVEL? WE PROPOSE TO MAKE A SYSTEMATIC ANALYSIS OF WHAT EFFECTS CAN IMPACT AN EMRI SYSTEM'S EVOLUTION. WE PLAN TO CATALOG BOTH HOW FAR ANALYSES MUST BE TAKEN AND WHAT EFFECTS MUST BE INCLUDED IN ORDER FOR EMRI MEASUREMENTS TO LIVE UP TO THEIR PROMISE., Studies of Strong-Gravity Binaries and Their Gravitational Waves
OpenAlex ID: W3152590962