Stretching the Limits of NR Bla Szilgyi, CalTech NRDA 2013 - PowerPoint PPT Presentation

NRDA 2013 September 18, 2013 Stretching the Limits of NR Béla Szilágyi, CalTech

NRDA 2013 Stretching the Limits of NR A new landscape in the “BBH business” ● After a long period of code development / optimization, the SpEC/CCC code has gained significantly in its robustness and efficiency Improved control of accuracy – Extended the region of parameter space where the code “just works” – (spin ~ 0.95, q ~ 10 ) Evolution speed has gained significantly – Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR A new landscape in the “BBH business” ● After a long period of code development / optimization, the SpEC/CCC code has gained significantly in its robustness and efficiency Improved control of accuracy – Extended the region of parameter space where the code “just works” – (spin ~ 0.95, q ~ 10 ) Evolution speed has gained significantly – NRAR had a significant role in this – it forced us to pull our act together. We automated mergers, implemented AMR, etc. Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR A new landscape in the “BBH business” ● The long desired goal of “ giving LIGO/VIRGO whatever they could ever want for BBH ” has come to within reach. Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR A new landscape in the “BBH business” ● The long desired goal of “giving LIGO/VIRGO whatever they could ever want for BBH” has come to within reach. ● Plans are twofold: We want to produce a large number of “ short ” waveforms (<100 1. cycles) Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR A new landscape in the “BBH business” ● The long desired goal of “giving LIGO/VIRGO whatever they could ever want for BBH” has come to within reach. ● Plans are twofold: We want to produce a large number of “ short ” waveforms (<100 1. cycles) Will work on Reduced Order Modeling, to span out the 7d (8d?) space 1. Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR A new landscape in the “BBH business” ● The long desired goal of “giving LIGO/VIRGO whatever they could ever want for BBH” has come to within reach. ● Plans are twofold: We want to produce a large number of “ short ” waveforms (<100 1. cycles) Will work on Reduced Order Modeling, to span out the 7d (8d?) space 1. In principle any interpolation mechanism or search algorithm can specify its 2. optimized input points Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR A new landscape in the “BBH business” ● The long desired goal of “giving LIGO/VIRGO whatever they could ever want for BBH” has come to within reach. ● Plans are twofold: We want to produce a large number of “ short ” waveforms (<100 1. cycles) Will work on Reduced Order Modeling, to span out the 7d (8d?) space 1. In principle any interpolation mechanism or search algorithm can specify its 2. optimized input points This stage may require a few thousand well selected runs. Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR A new landscape in the “BBH business” ● The long desired goal of “giving LIGO/VIRGO whatever they could ever want for BBH” has come to within reach. ● Plans are twofold: 1. Thousands of “ short ” waveforms 2. We plan to produce a selected set of “ long ” waveforms that reach back into the valid PN region. The goal is to help EOB and/or other semi-analytic models. We envision doing a few dozen of these. Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR A new landscape in the “BBH business” ● The long desired goal of “giving LIGO/VIRGO whatever they could ever want for BBH” has come to within reach. ● Plans are twofold: 1. Thousands of “ short ” waveforms 2. Dozens of “ long ” waveforms ● The various approaches would then be used to mutually check one another. Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR A new landscape in the “BBH business” ● The long desired goal of “giving LIGO/VIRGO whatever they could ever want for BBH” has come to within reach. ● Plans are twofold: 1. Thousands of “ short ” waveforms 2. Dozens of “ long ” waveforms ● The various approaches would then be used to mutually check one another. I’ll start with the “long” waveforms. I’ll talk about the “reduced basis” approach if time permits. Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR A 175 orbit, q=7 run ● Run pushed by Jonathan Blackman @ Caltech ● Low resolution just reached merger. Need another few days for a full (low-res) waveform. Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR A 175 orbit, q=7 run ● Run pushed by Jonathan Blackman @ Caltech ● Parameters: – Mass ratio 7, no spin – 350+ GW cycles to merger Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Computational cost / efficiency ● 48 cores – A typical BBH run fits onto a laptop , scaling to a large number of cores is difficult Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Computational cost / efficiency ● 48 cores ● O(Tbytes) of disk space – after post- processing this should decrease significantly Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Computational cost / efficiency ● 48 cores ● O(Tbytes) of disk space On a new cluster, with the latest code, this could be O(2-4) faster. Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Constraints ● Constraints drop when AMR adds resolution. ● The spike is the merger – the ringdown just started. Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Orbital frequency ● Orbital frequency: – Initial: 6.792e-3 – Merger: 2.44e-1 Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Orbital frequency ● Orbital frequency: – Initial: 6.792e-3 – Merger: 2.44e-1 ● The eccentricity is 0.00031, larger than usual. Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Orbital frequency ● Orbital frequency: – Initial: 6.792e-3 – Merger: 2.44e-1 ● Convergence is well preserved after >80 orbits. Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Orbital phase ● The high resolution phase error is < 0.1 radians at t = 67,000 M. (no alignment) Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Apparent Horizon Separation ● Convergence and eccentricity are both apparent. Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Irreducible Mass ● AhA is doing well. ● The O(1e-5) anomaly for AhB may be due to inaccurate AH finder settings. If so, the overall – run accuracy is not affected. Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Newtonian Center of Mass ● A long time-scale drift is seen. “short” runs could not – have seen this – Waveforms will tell how much of this is gauge. – Could be an outer boundary effect Colors: x, y, z Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Newtonian Center of Mass ● The oscillatory behavior is largely related to the “Newtonian” definition Colors: x, y, z Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Newtonian Center of Mass ● Junk Radiation induced features seem to be well resolved Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Newtonian Center of Mass ● Convergence is well preserved for 80+ orbits Colors: Lev0, Lev1, Lev2, Lev3 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Overlap with PN • We calculated the PN overlap with CCE waveforms, integrating up to some T0, measured back from merger. Overlap T0 0.9986 -60,000 0.9962 -50,000 0.9888 -40,000 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Overlap with PN • We calculated the PN overlap with CCE waveforms, integrating up to some T0, measured back from merger. Overlap T0 0.9986 -60,000 0.9962 -50,000 0.9888 -40,000 • Eccentricity, drift must have had an effect Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Overlap with PN • We calculated the PN overlap with CCE waveforms, integrating up to some T0, measured back from merger. Overlap T0 0.9986 -60,000 0.9962 -50,000 0.9888 -40,000 • Overlap falls below 0.99 at T0 < - 40,000 Béla Szilágyi, Caltech

NRDA 2013 Stretching the Limits of NR Summary of the long q=7 run ● This is a proof of principle. We can now reach into PN land. ● These runs take months. We’ll only do as many as helpful. ● Convergence is well preserved. ● We need to understand the Newtonian COM drift. Béla Szilágyi, Caltech