Inside the Most Powerful Explosions in the Universe: Birth of Black Holes, Jets, Heavy Elements, and Gravitational Waves

When a massive, rapidly spinning star dies, it doesn’t go quietly. It collapses into a black hole and launches the most powerful explosion in the universe, known as a collapsar. These events produce gamma-ray burst jets, forge black holes, and may even create the universe’s heaviest elements. Yet, despite decades of study, their inner workings have remained shrouded in mystery because of their vast dynamic scales and the non-linear physics that governs their collapse. In this talk, I will present the first 3D simulations of collapsars, which open a new window into their physics. I will show how we can determine the black hole’s natal mass, spin, and kick, and how the magnetic fields threading the black hole not only power the jets but also shape the surrounding accretion flow. This, in turn, governs heavy-element nucleosynthesis and gives rise to a new class of gravitational waves originating not from binary mergers but from turbulent disks. Finally, I will discuss the most massive relatives of collapsars - direct-horizon collapsars, which may be the origin of the recently observed most massive black hole merger event, GW231123.