Bulletin of the American Physical Society
APS April Meeting 2015
Volume 60, Number 4
Saturday–Tuesday, April 11–14, 2015; Baltimore, Maryland
Session U6: Numerical Relativity and Black Hole Binaries |
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Sponsoring Units: GGR Chair: Bruno Giacomazzo, Universidad de Trento Room: Key 2 |
Monday, April 13, 2015 3:30PM - 3:42PM |
U6.00001: Puncture Initial Data for Highly Spinning Black-Hole Binaries Ian Ruchlin, James Healy, Carlos Lousto, Yosef Zlochower Accretion arguments suggest that some astrophysical black-holes will possess nearly extremal spins. It is expected that gravitational wave signals from orbiting and merging black-hole binaries will be detected by Advanced LIGO in the next few years. Accurate waveform models are needed to interpret detector data. We solve the Hamiltonian and momentum constraints of General Relativity representing two black-holes with nearly extremal spins and ultra-relativistic boosts in the puncture formalism using spectral methods in the Cactus/Einstein Toolkit framework. We use a non-conformally-flat ansatz with an attenuated superposition of two conformally rescaled Lorentz-boosted-Kerr 3-metrics and their corresponding conformal extrinsic curvatures. The initial data are evolved in time using moving punctures in the BSSN and Z4 formalisms. We compare with the standard Bowen-York conformally-flat ansatz, finding an order of magnitude smaller burst of spurious radiation. [Preview Abstract] |
Monday, April 13, 2015 3:42PM - 3:54PM |
U6.00002: Asymptotically matched quasicircular binary black hole initial data William Throwe We demonstrate initial data for binary black hole simulations based on asymptotically matching a generic post-Newtonian binary metric with tidally deformed Schwarzschild solutions. These data have been evolved using the Spectral Einstein Code (SpEC) and have been shown to result in reduced junk radiation and smaller mass drift than our previous initial data sets. The use of a generic post-Newtonian binary metric for the near-field region allows us to adjust the eccentricity of simulated binaries, allowing for quasicircular simulations with eccentricities similar to those produced by previous initial data sets. [Preview Abstract] |
Monday, April 13, 2015 3:54PM - 4:06PM |
U6.00003: Constructing binary black hole initial data with high mass ratios and spins Serguei Ossokine, Francois Foucart, Harald Pfeiffer, Bela Szilagyi Binary black hole systems have now been successfully modelled in full numerical relativity by many groups. In order to explore high-mass-ratio (larger than 1:10), high-spin systems (above 0.9 of the maximal BH spin), we revisit the initial-data problem for binary black holes. The initial-data solver in the Spectral Einstein Code (SpEC) was not able to solve for such initial data reliably and robustly. I will present recent improvements to this solver, among them adaptive mesh refinement and control of motion of the center of mass of the binary, and will discuss the much larger region of parameter space this code can now address. [Preview Abstract] |
Monday, April 13, 2015 4:06PM - 4:18PM |
U6.00004: Comparing Post-Newtonian and Numerical-Relativity Precession Dynamics Lawrence Kidder, Sergei Ossokine, Michael Boyle, Harald Pfeiffer, Mark Scheel, Bela Szilagyi Binary black-hole systems are expected to be important sources of gravitational waves for upcoming gravitational-wave detectors. If the spins are not colinear with each other or with the orbital angular momentum, these systems exhibit complicated precession dynamics that are imprinted on the gravitational waveform. We develop a new procedure to match the precession dynamics computed by post-Newtonian (PN) theory to those of numerical binary black-hole simulations in full general relativity. For numerical relativity (NR) simulations lasting approximately two precession cycles, we find that the PN and NR predictions for the directions of the orbital angular momentum and the spins agree to better than $\sim1^{\circ}$ with NR during the inspiral, increasing to $5^{\circ}$ near merger. Nutation of the orbital plane on the orbital time-scale agrees well between NR and PN, whereas nutation of the spin direction shows qualitatively different behavior in PN and NR. We also examine how the PN equations for precession and orbital-phase evolution converge with PN order, and we quantify the impact of various choices for handling partially known PN terms. [Preview Abstract] |
Monday, April 13, 2015 4:18PM - 4:30PM |
U6.00005: Numerical relativity reaching into post-Newtonian territory: a compact-object binary simulation spanning 350 gravitational-wave cycles Mark Scheel, Bela Szilagyi, Jonathan Blackman, Tony Chu, Lawrence Kidder, Harald Pfeiffer, Alessandra Buonanno, Yi Pan, Andrea Taracchini We present the first numerical-relativity simulation of a compact-object binary whose gravitational waveform is long enough to cover the entire frequency band of advanced gravitational-wave detectors such as LIGO, Virgo and KAGRA, for mass ratio 7 and total mass as low as $45.5 M_\odot$. We find that effective-one-body models, either uncalibrated or calibrated against substantially shorter numerical-relativity waveforms at smaller mass ratios, reproduce our new waveform remarkably well, with a loss in detection rate due to modeling error smaller than $0.3\%$. In contrast, post-Newtonian inspiral waveforms and existing phenomenological inspiral-merger-ringdown waveforms display much greater disagreement with our new simulation. The disagreement varies substantially depending on the specific post-Newtonian approximant used. [Preview Abstract] |
Monday, April 13, 2015 4:30PM - 4:42PM |
U6.00006: Generic, Long, High Mass Ratio Binary Black Hole Inspiral Simulations Aaron Zimmerman, Adam Lewis, Harald Pfeiffer We present for the first time high mass ratio ($q = 5$ and $q=7$), long (40 - 50 pericenter passages), eccentric and precessing binary black hole inspirals. These inspirals are well suited for comparison to both analytic Post-Newtonian theory and to the motion of a small mass around a central black hole with gravitational self-force corrections. We discuss the properties of these inspirals, our initial comparisons, and future directions. [Preview Abstract] |
Monday, April 13, 2015 4:42PM - 4:54PM |
U6.00007: Expanding the catalog of binary black-hole simulations: aligned-spin configurations Tony Chu, Harald Pfeiffer, Mark Scheel, Bela Szilagyi A major goal of numerical relativity is to model the inspiral and merger of binary black holes through sufficiently accurate and long simulations, to enable the successful detection of gravitational waves. However, covering the full parameter space of binary configurations is a computationally daunting task. The SXS Collaboration has made important progress in this direction recently, with a catalog of 174 publicly available binary black-hole simulations [black-holes.org/waveforms]. Nevertheless, the parameter-space coverage remains sparse, even for non-precessing binaries. In this talk, I will describe an addition to the SXS catalog to improve its coverage, consisting of 95 new simulations of aligned-spin binaries with moderate mass ratios and dimensionless spins as high as 0.9. Some applications of these new simulations will also be mentioned. [Preview Abstract] |
Monday, April 13, 2015 4:54PM - 5:06PM |
U6.00008: Gravitational Waveforms in the Early Inspiral of Binary Black Hole Systems Kevin Barkett, Prayush Kumar, Swetha Bhagwat, Duncan Brown, Mark Scheel, Bela Szilagyi The inspiral, merger and ringdown of compact object binaries are important targets for gravitational wave detection by aLIGO. Detection and parameter estimation will require long, accurate waveforms for comparison. There are a number of analytical models for generating gravitational waveforms for these systems, but the only way to ensure their consistency and correctness is by comparing with numerical relativity simulations that cover many inspiral orbits. We've simulated a number of binary black hole systems with mass ratio 7 and a moderate, aligned spin on the larger black hole. We have attached these numerical waveforms to analytical waveform models to generate long hybrid gravitational waveforms that span the entire aLIGO frequency band. We analyze the robustness of these hybrid waveforms and measure the faithfulness of different hybrids with each other to obtain an estimate on how long future numerical simulations need to be in order to ensure that waveforms are accurate enough for use by aLIGO. [Preview Abstract] |
Monday, April 13, 2015 5:06PM - 5:18PM |
U6.00009: SXS Catalog of Gravitational Waveforms Daniel Hemberger Many aspects of gravitational-wave astronomy rely on numerical relativity for accurate models of gravitational waveforms. In recent years, several numerical relativity groups have built catalogs of numerical waveforms from binary black hole systems. I will report on the status of the Simulating Extreme Spacetimes (SXS) waveform catalog, which comprises simulations performed with the Spectral Einstein Code (SpEC). I will describe our approach for assessing numerical errors and convergence. Finally, I will discuss future plans to increase parameter space coverage of the catalog and to improve waveform accuracy. [Preview Abstract] |
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