Radio-telescope images providing insight into nova explosion gamma rays

24th October 2014 By: Leandi Kolver - Creamer Media Deputy Editor

Using highly detailed radio-telescope images, scientists have managed to pinpoint the locations where a classical nova stellar explosion emitted gamma rays, revealing a probable mechanism for the gamma-ray emissions, the University of Cape Town (UCT) said in a recent statement.

UCT explained that gamma rays had mystified astronomers when they were first observed, coming from a nova explosion, by the US National Aeronautics and Space Administration’s Fermi spacecraft, in 2012.

“Nova eruptions are the most common galactic explosions [and, therefore], this particular [nova] explosion was very interesting, because it was the first to produce gamma-ray emissions. There was a lot of interest in understanding its parameters,” UCT Square Kilometre Array (SKA) fellow Dr Valério Ribeiro explained.

Ribeiro said radio wavelengths were suitable for measuring the basic parameters of these explosions, such as their mass and how energetic the explosion was.

“However, many of the models applied, to date, have been assuming that the geometry of these explosions was spherical, since this is the easiest approximation,” he explained.

Ribeiro’s models, however, discovered that the eruption had a bipolar shape similar to a dumbbell, which contributed significantly to a better understanding of the process.

Michigan State University assistant professor Laura Chomiuk had worked with an international team of astronomers, including Ribeiro, to interpret the results of the radio-telescope images of the nova explosion.

“We not only found where the gamma rays came from, but also got a look at a previously unseen scenario that may be common in other nova explosions,” Chomiuk said in a paper that was recently published in the scientific journal Nature.

Further, UCT said that, once the SKA precursor MeerKAT radio telescope became operational, Ribeiro’s radio models would also be useful.

“We should start finding a number of these nova explosions and this will undoubtedly open up a whole new set of questions, as this Nature paper does,” Ribeiro commented, adding that the advent of the SKA should increase the science community’s understanding of these occurrences even further.

“Once the SKA comes online we will have the sensitivity and resolving power to observe more of these systems directly at further distances, allowing us to start exploring these systems – not just as individuals, but as populations,” Ribeiro said.