The One-Armed Spiral Instability in Neutron Star Mergers and its Detectability in Gravitational Waves

David Radice, Sebastiano Bernuzzi, and Christian D. Ott,
Phys. Rev. D. 94, 064011 (2016)


We study the development and saturation of the m=1 one-armed spiral instability in remnants of binary neutron star mergers by means of high-resolution long-term numerical relativity simulations. Our results suggest that this instability is a generic outcome of neutron stars mergers in astrophysically relevant configurations; including both "stiff" and "soft" nuclear equations of state. We find that, once seeded at merger, the m=1 mode saturates within ~10 ms and persists over secular timescales. Gravitational waves emitted by the m=1 instability have a peak frequency around 1−2 kHz and, if detected, could be used to constrain the equation of state of neutron stars. We construct hybrid waveforms spanning the entire Advanced LIGO band by combining our high-resolution numerical data with state-of-the-art effective-one-body waveforms including tidal effects. We use the complete hybrid waveforms to study the detectability of the one-armed spiral instability for both Advanced LIGO and the Einstein Telescope. We conclude that the one-armed spiral instability is not an efficient gravitational wave emitter. Its observation by current generation detectors is unlikely and will require third-generation interferometers.




You can read more about this paper on David Radice's homepage at

The Gravitational Waveforms generated by our simulations are available (and citable!) on at