Researchers reveal universe's most powerful explosions

A new study has provided a deeper insight into universe's most powerful explosions.

Research provided an inside look at gamma-ray bursts, which are considered the most powerful explosions in the universe.

These rare explosions happen when extremely massive stars go supernova. The stars' strong magnetic fields channel most of the explosion's energy into two powerful plasma jets, one at each magnetic pole. The jets spray energetic particles for light-years in both directions, at close to light speed.

On Earth, they detected bits of the resulting debris as gamma rays. Researchers also suspected, but haven't been able to prove conclusively, that GRBs are the source of at least some of the cosmic rays and neutrinos that pepper our planet from space.

Now, physicists at The Ohio State University and their colleagues have begun to answer that question. By building some of the most detailed computer simulations ever made of a GRB jet's internal structure, they have been able to model particle production inside of it.

Their findings suggested that the non-uniform internal structure of the jets was key to determining the emission of the different kinds of astroparticles.

The study also raised new questions that can be answered only by the next generation of neutrino telescopes.

With partners at Penn State and the DESY national research center in Germany, Bustamante wrote new computer code to take into account the shock waves that are likely to occur within the jets. They simulated what would happen when blobs of plasma in the jets collided, and calculated the particle production in each region.

In their model, some regions of the jet are denser than others, and some plasma blobs travel faster than others.

Mauricio Bustamante, a Fellow of the Center for Cosmology and AstroParticle Physics at Ohio State, explained that the new computer model was a natural outgrowth of recent findings in astroparticle physics, such as the first confirmed cosmic neutrinos detected at the IceCube Neutrino Observatory at the South Pole in 2013.

The amount of debris that reaches Earth depends on how energetic the star was and how far away it was.

One implication of the model is that the rate of neutrino production in GRBs might be lower than previously thought, so only a minimal number; say, 10 percent, of neutrinos detected on Earth are likely to come from GRBs.

The density of neutrinos that reach Earth was called the neutrino flux, and the model predicted that the likely neutrino flux from GRBs was below the threshold of detection for today's neutrino telescopes.

The study is published in the journal Nature Communications.