A catalog of long, eccentric and precessing binary black hole simulations from ICTS-TIFR

Abstract

We present a catalogue of 31 binary black hole simulations performed with the Spectral Einstein Code (SpEC) on the Sonic cluster at ICTS-TIFR, Bengaluru between August 2023 and December 2024, targeting the sparsely covered corner of parameter space in which orbital eccentricity and spin-orbit precession are present simultaneously: 17 configurations are both eccentric and precessing, spanning mass ratios $1 \le q \le 11$ and initial eccentricities up to $\hat{e}_0 = 0.40$. The longest, EccPrecDiff002, inspirals for 80 orbits (159 gravitational-wave cycles), to our knowledge the longest simultaneously eccentric and precessing binary black hole evolution to date. Compile-time optimisation of SpEC and its third-party library stack for the AMD Zen-2 architecture delivered a 90% speedup of the initial-data solver and a 40% speedup of the evolution, roughly half of the latter traceable to a single defect in how pre-2.34 glibc reported cache topology on AMD processors. The campaign consumed $1.18 \times 10^{6}$ CPU-hours. We document the post-processing pipeline and validate the frame transformation and waveforms. Eccentricity is measured from the waveforms and compared against the initial data. The first law of binary black hole mechanics, a test of approximate helical symmetry, is satisfied to better than 0.54% for every configuration with $e_ω < 0.2$, and we show that even precessing systems can be regarded as possessing approximate helical symmetry in the co-precessing frame. Using the aligned-spin simulations to calibrate the numerical floor, the co-precessing approximation&#39;s mirror-symmetry violation lies three to four ordersof magnitude above it, growing from 0.7% to 5.3%with opening angle. EccPrecDiff002 spans the band above 5 Hz without hybridisationfor $M \le 62\,M_\odot$, giving a single-interferometer signal-to-noise ratio of 961 in Cosmic Explorer at 1 Gpc.