Study of the most brightest explosions of the universe by supercomputer simulations

Imagine an explosion so powerful it can outshine our Sun by a hundred quintillion, that is 10 to the 20th power. These are gamma-ray bursts (GRBs), the most intense explosions in the cosmos since the Big Bang. GRBs occur either when a massive star collapses or when two compact objects (two neutron stars or a neutron star and a black hole) merge. In both scenarios, a black hole forms, and the surrounding gas spirals inward, launching twin jets at nearly the speed of light.

In just seconds, a single GRB can release more energy than the Sun emits in its entire ten-billion-year lifetime. These cosmic cataclysms forge many of the universe’s heavy elements and send ripples through spacetime, the gravitational waves, which we detect on Earth today and will observe in even greater detail with future space-based interferometers. Because no Earthbound experiment can recreate these extreme conditions, we employ numerical simulations performed in super-computers. By modeling the furious interplay of gas, magnetic fields, and gravity, we reveal how jets ignite, how light is produced, and what signatures to seek with telescopes and gravitational-wave detectors.

In this talk, I will guide you through the physics of GRBs, showing our simulation techniques, and highlight key insights into these spectacular cosmic explosions.