A Parametric Study of the SASI Comparing General Relativistic and Nonrelativistic Treatments

TL;DR

This study compares the effects of general relativity versus nonrelativistic physics on the standing accretion shock instability in supernova models, revealing significant differences in oscillation periods and growth rates.

Contribution

It provides a systematic numerical comparison of GR and NR treatments of SASI across different proto-neutron star compactnesses in supernova simulations.

Findings

GR increases SASI oscillation period by up to 29%.

GR reduces SASI growth rate by up to 53%.

Results have implications for supernova modeling accuracy.

Abstract

We present numerical results from a parameter study of the standing accretion shock instability (SASI), investigating the impact of general relativity (GR) on the dynamics. Using GR hydrodynamics with GR gravity, and nonrelativistic (NR) hydrodynamics with Newtonian gravity, in an idealized model setting, we vary the initial radius of the shock and, by varying its mass and radius in concert, the proto-neutron star (PNS) compactness. We investigate four compactnesses expected in a post-bounce core-collapse supernova (CCSN). We find that GR leads to a longer SASI oscillation period, with ratios between the GR and NR cases as large as 1.29 for the highest-compactness suite. We also find that GR leads to a slower SASI growth rate, with ratios between the GR and NR cases as low as 0.47 for the highest-compactness suite. We discuss implications of our results for CCSN simulations.