Constraining the Neutron Star Equation of State with Gamma-ray Bursts

Cecilia Chirenti (University of Maryland)

September 16, 2024

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Abstract: Short gamma ray bursts (GRBs) have already been associated with binary neutron star mergers, which are also sources of gravitational waves. Numerical relativity simulations indicate that the merger can form a short-lived hypermassive neutron star (which could produce a millisecond magnetar), lasting for tens to hundreds of milliseconds before gravitational collapse forms a black hole. This neutron star remnant is expected to emit gravitational waves (GWs) with kHz frequencies that will be detectable by third generation ground-based GW detectors in the 2030s. Recently, kHz quasiperiodic oscillations were discovered in GRBs 910711 and 931101B, providing evidence for a hypermassive neutron star stage in these events. When analyzed together with new quasi-universal relations obtained from numerical relativity simulations, these detections provide a novel method to constrain the equation of state of the dense matter in neutron star cores.