Speaker
Description
By identifying quasi-periodic oscillations reported in FRB 20240114A (from the Five-hundred-meter Aperture Spherical Telescope) with neutron star crustal torsional oscillations, together with experimental constraints on the nuclear saturation parameter, the incompressibility $K_0$, we constrain the mass and radius of an extragalactic neutron star at redshift $z=0.13$. Identifying the low-order QPO frequencies as fundamental oscillations, and frequencies of 567.7 Hz or 655.5 Hz (rest frame) as first overtone candidates implies neutron star mass ranges of $1.00-1.55 M_\odot$ or $1.17-1.76 M_\odot$, respectively. Additionally, accounting for the nuclear parameter dependence of low-mass neutron star structure yields an estimated radius of $12.5-13.5$ km. Simultaneously, we also constrain the nuclear saturation parameter, namely the density dependence of the nuclear symmetry energy, $L$, and determine it to be $L=59.5-96.8$ MeV, which is broadly consistent with the previous constraints on $L$ obtained from the experiments and astronomical observations. This can be investigated with upcoming FRB surveys over a broad range of redshifts and more elaborate data analyses.
| Category | Theory |
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