Title:	Astrophysics at the Extremes: The Death of Massive Stars
DNr:	NAISS 2025/3-42
Project Type:	NAISS Large
Principal Investigator:	Evan Patrick O'Connor <evan.oconnor@astro.su.se>
Affiliation:	Stockholms universitet
Duration:	2026-01-01 – 2027-01-01
Classification:	10305
Homepage:	http://www.evanoc.com
Keywords:

Abstract

Due to the extreme energies involved in core-collapse supernovae (CCSNe), they are a cornerstone of astronomy and astrophysics. CCSNe are the site where neutron stars and black holes are formed and, therefore, a gateway to our study of high-energy astrophysics. The incredible amount of 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. Despite the importance of CCSNe in astrophysics and over 60 years of intense numerical effort, their inner workings are only now becoming clear. Our advanced understanding of CCSNe is due to our ability to accurately simulate these events on modern supercomputers with massively parallel, multidimensional, neutrino-radiation magnetohydrodynamical simulations. Today, the general consensus is that we understand the basics of the mechanism behind typical CCSNe. This large allocation has two major focuses. First, this large allocation has a special emphasis on the central engines of extreme supernovae. Extreme supernovae, likely those involved in producing BHs or extremely bright and rare transients such as super-luminous supernovae or gamma-ray burst supernovae are relatively (compared to typical supernovae) poorly understood. Even rare transients will be well observed in upcoming all-sky surveys like LSST, and therefore solidifying the underlying theory is critical. Second, this allocation will simulate the core-collapse phase of recently produced multidimensional progenitor models, which are thought to play a critical role in seeding the turbulence needed for the explosion to develop. In both cases, we will achieve our research goals with state-of-the-art multidimensional radiation magnetohydrodynamic simulations using the FLASH code. This large allocation is a continuation of NAISS 2024/3-32. We are proposing here to build upon the results of our previous allocation with the following two computational work packages. CWP #1: 3D neutrino-radiation (magneto)hydrodynamic simulations of core-collapse in extreme progenitor stars with the aim of connecting the core physics to observations of extreme transients. Request: 600 × 1000 core hours/month. CWP #2: 3D neutrino-radiation hydrodynamic simulations of core-collapse from recent massive star progenitors evolved in 3D for that last ~10 minutes of iron core burning. Request: 400 × 1000 core hours/month.