Gravitational memory in binary black hole mergers - General Relativity and Quantum CosmologyReport as inadecuate

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Abstract: In addition to the dominant oscillatory gravitational wave signals producedduring binary inspirals, a non-oscillatory component arises from the nonlinear-memory- effect, sourced by the emitted gravitational radiation. The memorygrows significantly during the late inspiral and merger, modifying the signalby an almost step-function profile, and making it difficult to model byapproximate methods. We use numerical evolutions of binary black holes toevaluate the nonlinear memory during late-inspiral, merger and ringdown. Weidentify two main components of the signal: the monotonically growing portioncorresponding to the memory, and an oscillatory part which sets in roughly atthe time of merger and is due to the black hole ringdown. Counter-intuitively,the ringdown is most prominent for models with the lowest total spin. Thus, thecase of maximally spinning black holes anti-aligned to the orbital angularmomentum exhibits the highest signal-to-noise SNR for interferometricdetectors. The largest memory offset, however, occurs for highly spinning blackholes, with an estimated value of h^tot 20 \approx 0.24 in the maximallyspinning case. These results are central to determining the detectability ofnonlinear memory through pulsar timing array measurements.

Author: Denis Pollney, Christian Reisswig



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