Astrophysics at the Extremes: The Death of Massive Stars
Title: Astrophysics at the Extremes: The Death of Massive Stars
DNr: NAISS 2023/3-38
Project Type: NAISS Large Compute
Principal Investigator: Evan Patrick O'Connor <>
Affiliation: Stockholms universitet
Duration: 2024-01-01 – 2025-01-01
Classification: 10305


Astrophysical environments at the extremes play crucial roles in astronomy, as well as being extraordinary laboratories for studying fundamental physics. One of these, Core-Collapse Supernovae (CCSNe), result when a massive star reaches the end of its life, collapses, and then violently explodes. In astronomer's and physicist’s attempts to understanding the history of the Universe, these explosions play many roles. They are the site where neutron stars and black hole are formed and therefore a gateway to our study of high energy astrophysics; the incredible energy released in these events drives the evolution of galaxies; and the elements forged and dispersed by the explosion are the building blocks of life as we know it. For over 60 years, intense research has gone into understanding the implosion and subsequent explosion of these massive stars. Progress has always been driven by numerical simulations at the forefront of our high performance computing abilities. Only recently have we reached the stage where the computing power available is enough to handle the demands sets by the physics. Modern simulations of CCSNe are readily achieving successful explosions, especially in 2D, but also, importantly, in 3D. What is learned from these simulations will represent a leap forward in our understanding of the connected astrophysics. With this allocation, we propose to continue our exploration of CCSNe with the FLASH code. For this large allocation, we propose three research directions (computational work packages; CWPs) for our multidimensional CCSNe simulations in support of the PI’s VR Consolidator Grant during 2021-2026. CWP #1:Black Holes from Extreme Supernovae with FLASH-M1. This project will focus on black hole formation in both neutrino-driven explosions and in magneto-rotational driven explosions using full energy-dependent neutrino transport. CWP #2: Systematic Exploration of Supernova Physics with FLASH-Grey. A new efficient neutrino scheme allows us to systematically explore CCSNe in multiple dimensions providing a clearer picture of the progenitor and equation of state dependence at a fraction of the computational cost. CWP #3: Post-explosion with FLASH-star. Following the explosion throughout the entire star in order to determine the final remnant structure and composition for use in predicting the final remnant properties and the electromagnetic signals.