Cracking Neutron star mysteries: from Interior to surface and exterior

The utilization of Pulse Profile modeling techniques could simultaneously provide measurements for Neutron star Mass Radius and offer insights into their hotspot distribution. Presently, these methodologies rely on meta models of the equation of state (EOS) and employ pure geometrical cap overlapping techniques to align with observational data. This presentation aims to showcase our recent results about utilizing a physics-oriented EOS and more EOS-independent ways to explore the constraint of X-ray timing observations on fundamental physics parameters governing neutron star's structure. Additionally, I have launched an international collaboration aimed at open-sourcing and standardizing the whole analysis pipeline in a package called CompactObject : See https://github.com/ChunHuangPhy/CompactObject

Furthermore, I will present a Physics-motivated computation of neutron star hotspot temperature maps given by PSR J0030+0451 and PSR J0437-4715 NICER measurements about its magnetic configuration. Using a theoretical model for the electric current density in a force-free pulsar magnetosphere, we compute from first principles the temperature distribution over the polar cap associated with an off-center magnetic dipole.  In this study, I apply MCMC fitting to the X-ray light curves of pulsars PSR J0030+0451 and PSR J0437-4715 with and without the volumetric return current and find that our model can reasonably recover the observed X-ray light curves