Speaker
Description
Understanding the Galactic population of isolated neutron stars within a unified framework provides key insights into their birth properties, evolutionary pathways, and the connections between different neutron star classes. In this work, we combine observational data from radio pulsars and isolated neutron stars exhibiting quiescent X-ray emission, employing a comprehensive population synthesis approach to investigate their origin and evolution. We develop a flexible population synthesis framework that models the dynamical, rotational, and magneto-thermal evolution of neutron stars, their radio and X-ray emission, and the selection effects of radio and X-ray surveys. Our models incorporate state-of-the-art 2D magneto-thermal simulations, allowing us to explore the impact of varying magnetic field configurations and envelope compositions. To simulate realistic X-ray spectra, we account for magnetospheric resonant cyclotron scattering and interstellar absorption. Additionally, we model the observational bias introduced by magnetar outbursts by linking the outburst rate to magnetic stresses in the stellar crust. We employ a simulation-based inference technique using artificial neural networks to reconstruct the birth properties, such as the initial magnetic field distribution and long-term magnetic field decay of the neutron star population. By combining radio and X-ray data we provide new constraints on the overall neutron star birth rate in the Galaxy and on the fraction of neutron stars exhibiting magnetar-like properties. This in turn can help quantify magnetar potential contribution to explain the rate of astrophysical transient phenomena, such as super-luminous supernovae, gamma-ray bursts and fast radio bursts.
