Speaker
Description
In spider pulsar binaries, the energetic pulsar wind continuously ablates the low-mass companion star, driving a complex intrabinary shock and producing a dense local plasma-filled environment. This interaction region acts as a unique laboratory for high-energy astrophysics, yet its precise geometry and local properties remain challenging to constrain. In this work, we present a theoretical modelling framework to investigate the physical conditions of the intrabinary shock through simulated frequency-dependent radio eclipses. Our simulations show that treating the intrabinary shock as a finite three-dimensional volume, with a smoothly varying plasma-density distribution, produces more realistic eclipse morphologies than an idealised thin-shell treatment. The three-dimensional geometry further shows how the orbital motion of the system can sweep the ablated plasma into a cometary tail, naturally producing an asymmetric eclipse via a delayed egress. Furthermore, the model demonstrates how the shock stand-off distance and orbital inclination strongly influence the overall extent of the radio eclipse. By demonstrating the model's behaviour and sensitivity to shock geometry, density weighting, and geometry, this framework provides a robust foundation for interpreting complex propagation effects and for further model development in future. Inferences from this model are complementary from conclusions drawn from high-energy data, adding to a holistic picture of spider binaries.