Title: Fast Rotating Neutron Stars: Spectra, Stability and Universal Relations

Place: Seminar del DAA. Jeroni Muñoz Research Building, fourth floor, in Burjassot.

Day: Friday, may 8 , 2026. Time: 12.00.

Abstract:

In the first part of this talk, we study rapidly rotating relativistic stars which are present in various astrophysical systems. We study their oscillations and instabilities by taking into account the contribution of a dynamic space-time. By linearising the Einstein equations, the oscillation frequencies as well as the critical values for the onset of a secular instability are determined. We show asteroseismological relations for the fundamental eigenfrequency which are crucial for tackling the inverse problem. Secondly, we provide universal relations that allow to estimate bulk quantities of neutron stars from the knowledge of the triple mass, radius and moment of inertia of an associated non-rotating star. The proposed universal relations facilitate computationally cheap EOS inference codes that permit the inclusion of observations of rotating neutron stars. As a demonstration, we deploy them into a Bayesian framework for equation of state parameter estimation that works for arbitrary, uniform rotation.