Determine the size and shape of accretion mounds

Determine the size and shape of accretion mounds formed where low-rate accretion flows decelerate and merge with the neutron-star surface.

Background

At subcritical accretion rates, matter may be stopped by collisionless shocks or Coulomb interactions near the neutron-star surface. Because cross-field transport is suppressed by the strong magnetic field, some material is expected to accumulate in a magnetically confined mound, whose geometry directly affects emission-region modeling and pulse profiles.

References

The size and shape of these mounds is still unknown.

— Pulse profiles of accreting neutron stars - A review of analysis methods, observations, and theoretical models  (2608.20876 - Pottschmidt et al., 21 Aug 2026) in Section 2.2.2, “Subcritical accretion: Collisionless shock and Coulomb collisions”