Heidelberg 2022 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
GR: Fachverband Gravitation und Relativitätstheorie
GR 11: Relativistic Astrophysics
GR 11.2: Talk
Thursday, March 24, 2022, 11:20–11:40, GR-H2
Tidally-driven crustal failure in coalescing binaries of neutron stars as triggers for precursor flares of short gamma-ray burst — •Hao-Jui Kuan1,2, Arthur Suvorov3, and Kostas Kokkotas1 — 1Theoretical Astrophysics, IAAT, University of Tübingen, Tübingen, D-72076, Germany — 2National Tsing Hua University, Hsinchu 300, Taiwan — 3Manly Astrophysics, 15/41-42 East Esplanade, Manly, NSW 2095, Australia
In some short gamma-ray bursts, precursor flares occurring ∼ seconds prior to the main episode have been observed. These flares may then be associated with the last few cycles of the inspiral when the orbital frequency is a few hundred Hz. During these final cycles, tidal forces can resonantly excite quasi-normal modes in the inspiralling stars, leading to a rapid increase in their amplitude. It has been shown that these modes can exert sufficiently strong strains onto the neutron star crust to instigate yieldings. Among other possible modes, the typical frequencies of g-modes being ∼ 100 Hz warrant further investigation since their resonances with the orbital frequency match the precursor timings. Adopting realistic equations of state (EOS) and solving the general-relativistic pulsation equations, we study g-mode resonances in coalescing quasi-circular binaries, where we consider various stellar rotation rates, degrees of stratification, and magnetic field structures. We show that for some combination of stellar parameters, the resonantly excited g1- and g2-modes may lead to crustal failure and trigger precursor flares, and also some EOS are more likely to cause the crustal cracks.