May 26 – 28, 2025
Universidad de Alcalá
Europe/Madrid timezone

Fastest spinning millisecond pulsars as indicators of deconfined quark matter in neutron stars

May 27, 2025, 12:00 PM
30m
Universidad de Alcalá

Universidad de Alcalá

Colegio de San Ildefonso, Plaza de San Diego, s/n, 28801 Alcalá de Henares, Madrid.

Speaker

Dr Violetta Sagun (University of Southampton)

Description

We study rotating hybrid stars with a particular emphasis on the effect of a deconfinement phase transition on their properties at high spin. Our analysis is based on a hybrid equation of state with a phase transition from hypernuclear matter to color-superconducting quark matter, where both phases are described within a relativistic density functional approach. By varying the vector meson and diquark couplings in the quark matter phase, we obtain different hybrid star sequences with varying extensions of the quark matter core, ensuring consistency with astrophysical constraints from mass, radius, and tidal deformability measurements. We test whether the early deconfinement phase transition is consistent with the present observational data. We show how the fastest spinning pulsars, the appearance of the quasi-radial oscillations, and non-axisymmetric instabilities constrain the strongly interacting matter equation of state at zero temperature. Our findings reveal that incorporating the hybrid equation of state into the analysis of pulsars has significant implications for the constraints on the properties of strongly interacting matter and neutron stars.

Primary author

Dr Violetta Sagun (University of Southampton)

Co-authors

Christoph Gärtlein (CENTRA, Instituto Superior Técnico/ University of Coimbra/ University of Wroclaw) David Blaschke (University of Wroclaw/ Helmholtz-Zentrum Dresden-Rossendorf/Center for Advanced Systems Understanding) Ilidio Lopes (CENTRA, Instituto Superior Técnico) Oleksii Ivanytskyi (University of Wroclaw)

Presentation materials