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Astronomers astonished: distant radio bursts strongly resemble neutron stars
from Contact 17
BY ASTRON COMMUNICATIONS
Astronomers have discovered 24 of the as-yet-unexplained fast radio bursts (FRBs) which have a striking similarity to the radio flashes emitted by nearby, known neutron stars.
The findings, published in Astronomy and Astrophysics, were made using the Westerbork Synthesis Radio Telescope’s Apertif system, an SKA pathfinder technology. They add weight to the theory that neutron stars could be the origin of the mysterious bursts.
The discovery is remarkable because these nearby neutron stars already produce more energy than anything achievable on Earth. The distant stars that emit the FRBs must somehow generate an astounding one billion times more energy than the nearby ones.
FRBs last only about one millisecond, but in that short time they produce more energy than the Sun creates in a month. Up to now, the record holders for power generation were neutron stars, the remnants of exploded stars in our own Milky Way galaxy. The gravity, density and radiation around such neutron stars already amounted to some of the most extreme environments known, visible out to distances of about 100,000 light years. The newly found FRBs, however, shine a billion times more radiantly than neutron stars, reaching Earth from up to one billion light years away, far outside our Milky Way.
Lead author Dr Inés Pastor-Marazuela (ASTRON and University of Amsterdam) explains: “We were able to study these bursts in an incredible level of detail. We find that their shape is very similar to what we see in young neutron stars.”
Dr Pastor-Marazuela, currently a Dutch Research Council (NWO) Rubicon Fellow at The University of Manchester, adds that the way the radio flashes were produced and modified as they travelled through space also supports a neutron star origin.
The astronomers achieved this detailed analysis using ARTS, the Apertif Radio Transient System, an experimental supercomputer specifically designed for studying FRBs. In real time it creates and searches well over 1,500 radio beams, the number the SKA-Mid telescope will produce.
“We generally do not know when or where the next FRB will appear,” says research leader Dr Joeri van Leeuwen (ASTRON), “so we have a vast computer constantly crunch through all radio signals from the sky.”
The system automatically searches for very short, bright bursts from great distances, then zooms in on the data and alerts astronomers.
“We were just starting to think we were getting close to understanding how regular neutron stars can shine so exceedingly bright in radio,” says Dr van Leeuwen.
“But then the Universe comes along and makes the puzzle one billion times harder. That’s just great.”
