An international team of scientists led by researchers at McGill University has provided the strongest evidence yet that some fast radio bursts (FRBs) originate from neutron stars - the dense remnants of massive stars that exploded as supernovae. By analyzing the radio signals of individual FRBs, this study provides new insights into these mysterious, millisecond-long bursts of radio waves coming from space, advancing our understanding of one of the most puzzling phenomena in the universe.
"This result reaffirms long-held suspicions about the connection between FRBs and neutron stars," said Ryan Mckinven, a doctoral researcher in the Department of Physics at McGill University and corresponding author of the study published in Nature. "However, our findings also challenge popular theoretical models, providing evidence that radio emission occurs much closer to neutron stars than previously thought."
FRBs release as much energy in a few milliseconds as the sun does in an entire day. Scientists have detected thousands of such bursts since their discovery in 2007, but their origins and mechanisms remain elusive. Mckinven's study using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope found that the behavior of FRB signals bears striking similarities to that of pulsars, a well-studied class of radio neutron stars.
FRB signals typically have highly polarized properties, meaning that the radio waves primarily oscillate along a specific, well-defined direction. By studying the polarization of the FRB signal, Mckinven's team observed that its angle changed dramatically during the burst's 2.5 millisecond duration, which is typical of pulsars but rare in FRBs. This striking feature initially led to suspicion that the signal might come from a misclassified pulsar in the Milky Way. However, further analysis confirmed that the FRB originated in a galaxy millions of light-years away.
"Polarization measurements are one of the few tools we have to detect these distant sources," McGinn explains. "This result is likely to inspire follow-up studies of similar behavior in other FRBs and prompt theoretical efforts to reconcile differences in their polarization signals."
This research highlights the value of the CHIME telescope in Penticton, British Columbia, which is known for its unparalleled ability to detect thousands of FRBs per day. The vast amount of data from CHIME allows scientists to identify unique signals like this one, adding to a broad understanding of FRBs.
"This is one step closer to unraveling a profound cosmic mystery. FRBs are everywhere, but their true nature remains largely unknown. Every discovery we make about their origins opens a new window into the dynamics of the universe."
In a study of the same FRB published in the same issue of Nature, MIT lead researcher Kenzie Nimmo provided more support for the neutron star conjecture.
"We found that this FRB exhibits a 'sparkle,' similar to stars twinkling in the night sky. Observing this flicker suggests that the region of origin of the FRB must be very small. Even though the FRB originates 200 million light-years away, we pinpointed the emission point to less than 10,000 kilometers in size." "This extraordinary precision reveals that the FRB must have originated from the intense magnetic environment around neutron stars, one of the most extreme environments in the universe," Nimmo said.
Together, research led by McGinn and Nimmo provides strong evidence that this and other FRBs originate from neutron stars.
"These observations provide a rare glimpse into what we can see," said Aaron Pearlman, a Banting Prize postdoctoral researcher in McGill University's Department of Physics and the Trottier Institute for Space Studies and a co-author of the study led by McGinn and Nimmo. "
Compiled from /ScitechDaily