(14.03.2022) For the first time in international science, researchers from the Dublin Institute for Advanced Studies (DIAS) have observed a cosmic explosion with unprecedented detail and witnessed particle acceleration outside our solar system.

DIAS scientists, including: Dr. Jonathan Mackey, Prof. Felix Aharonian, Dr. Robert Brose and Dr. Davit Zargaryan are members of an international team that was able to observe this acceleration process for the first time, due to specialist telescopes which were used at the HESS (High Energy Stereoscopic System) facility in Namibia.

The team observed a nova explosion – a violent eruption from the surface of a star – in August 2021, from a binary star system called “RS Ophiuchi”.  This led to the discovery that particles from the explosion were accelerated to energies several hundred times higher than previously observed from novae.

The team also observed that energy released from the explosion was transformed extremely efficiently into accelerated protons and heavy nuclei, such that the particle acceleration reached the maximum rate calculated in theoretical models.

Dr. Mackey was part of a four-person team that worked on creating a theoretical model to interpret the data from the observations, while all four DIAS scientists were involved in developing the manuscript and were co-authors of the research findings, which have recently been published in Science.

Commenting today (14.03.22), Professor Aharonian said: “I am proud to have led DIAS’s involvement in this ground-breaking international research team. This discovery will have profound consequences for astrophysics, as it has changed our understanding of particle acceleration in our universe.

“During the eruption of RS Ophiuchi, the team was able to observe the eruption with an unprecedented level of detail thanks to the sophisticated telescopes at the HESS facility. This enabled the team to examine the particle acceleration in real time. They discovered that particles produced from the eruption reached energy levels significantly higher than previously recorded. In effect, they reached what we thought would have been their maximum acceleration rate.”

Also commenting, Dr. Jonathan Mackey, leader of the high-energy astrophysics group at DIAS, said: “The findings from this research will be key in helping us to understand how cosmic explosions work. DIAS is one of the founding members of the HESS experiment, which has been running now for almost 20 years from Namibia. By using the enhanced telescopes at the HESS facility, we will be able to study future nova explosions to assess whether RS Ophiuchi was unusually energetic or whether all nova explosions generate similar levels of particle acceleration. Discoveries such as these show the value of investing in scientific research to help strengthen our understanding of the universe we inhabit.”

The imaging technique used by the HESS telescopes (Atmospheric Cherenkov Telescope technique) was pioneered by Irish scientists, Professor Neil Porter and Professor Trevor Weekes, in Ireland in the 1960s.  Professor Weekes led the team that made the first successful detection of the Crab Nebula using this technique in 1989.