Tons of of gamma-ray bursts (GRBs) have been recorded as a part of an unlimited global effort so extensive it “rivals the catalogue of deep-sky objects created by Messier 250 years ago,” astronomers say.
GRBs are essentially the most violent explosions within the Universe, releasing more energy than the Sun would in 10 billion years. They occur when either a large star dies or two neutron stars merge.
The explosions are so formidable that if one were to erupt inside a distance of 1,000 light-years from Earth — which is predicted to occur every 500 million years — the blast of radiation could damage our ozone layer and have devastating consequences for all times. Nevertheless, the probabilities of such an event occurring any time soon are extremely low.
First observed almost six many years ago, GRBs even have the potential to assist us higher understand the history of our Universe, from its earliest stars to the way it looks today.
The newest research recorded 535 GRBs — the closest of which was 77 million light-years from Earth — from 455 telescopes and instruments the world over.
It was led by Professor Maria Giovanna Dainotti, of the National Astronomical Observatory of Japan, and has been published today within the Monthly Notices of the Royal Astronomical Society.
The researchers likened their collection to the 110 deep-sky objects catalogued by the French astronomer Charles Messier within the 18th century. To this present day the catalogue continues to offer astronomers — each skilled and amateur — with a variety of easy-to-find objects within the night sky.
“Our research enhances our understanding of those enigmatic cosmic explosions and showcases the collaborative effort across nations,” said Professor Dainotti.
“The result’s a listing akin to the one created by Messier 250 years ago, which classified deep-sky objects observable at the moment.”
It has been hailed by co-author Professor Alan Watson, of the National Autonomous University of Mexico, as a “great resource” that would help “push the frontiers of our knowledge forward.”
Professors Watson and Dainotti were a part of a team of greater than 50 scientists who meticulously studied how GRB light reaches Earth over several weeks and, in some cases, even months after the explosion. The result, they are saying, is the most important catalogue ever assembled of GRBs observed in optical wavelengths with measured distances.
It includes 64,813 photometric observations collected over 26 years, with notable contributions from the Swift satellites, the RATIR camera, and the Subaru Telescope.
What the team found particularly interesting about their findings was that just about a 3rd of the GRBs recorded (28 per cent) didn’t change or evolve as the sunshine from the explosions travelled across the cosmos.
Co-author Dr Rosa Becerra, of the University of Tor Vergata in Rome, said this implies that a few of the most up-to-date GRBs behave in the exact same way as those which occurred billions of years ago.
Such a finding is at odds with the massive picture commonly seen within the Universe, where objects have repeatedly evolved from the Big Bang.
Professor Dainotti added: “This phenomenon could indicate a really peculiar mechanism for the way these explosions occur, suggesting that the celebs linked to GRBs are more primitive than those born more recently.
“Nevertheless, this hypothesis still needs more investigation.”
Then again, for the few GRBs where this optical evolution matches the X-ray evolution, a more straightforward explanation is feasible.
“Specifically, we’re observing an expanding plasma composed of electrons and positrons that cools over time, and like a hot iron rod radiating redder and redder light because it cools, we do see a transition of the emission mechanism,” said fellow researcher Professor Bruce Gendre, of the University of the Virgin Islands.
“On this case, this mechanism could also be linked to the magnetic energy that powers these phenomena.”
The researchers now want the astronomical community to assist expand their GRB compilation further. They’ve made the info accessible through a user-friendly web app and have called on their peers so as to add to it, ideally by sharing findings in the identical format.
“Adopting a standardised format and units, potentially linked to the International Virtual Observatory Alliance protocols, will enhance the consistency and accessibility of the info on this field,” Professor Gendre said.
“Once the info are secured, additional population studies shall be conducted, triggering recent discoveries based on the statistical evaluation of the present work.”
