An international team of astrophysicists, led by Northwestern University and the University of Leicester in England, has uncovered a possible origin of fast X-ray transients (FXTs) — mysterious, fleeting bursts of X-rays that have long puzzled astronomers.
Using a combination of telescopes around the globe and in space, the team studied the closest FXT associated with the explosive death of a massive star, or supernova, ever observed. A geyser of high-energy particles, or jet, trapped inside a supernova produced the FXT, the scientists discovered.
When jets burst through a massive star’s onion-like layers, they generate gamma-ray bursts (GRBs), the most powerful and luminous explosions in the universe. When the jets are stifled, however, they emit lower levels of energy, which astronomers can detect only from X-ray signals. The new observations now point to these “failed” jets as a source of the emission, explaining the historically elusive phenomena.
This finding marks a significant step in understanding the diverse landscape of cosmic explosions — bridging the gap among FXTs, GRBs and supernovae. Two companion studies, detailing various aspects of the event, have been accepted by The Astrophysical Journal Letters. (Both papers are available on ArXiv: Rastinejad et. al. and Eyles-Ferris et. al.)
“Since the 1970s, astronomers have detected FXTs — blasts of X-rays from distant galaxies that can last from seconds to hours,” said Northwestern’s Jillian Rastinejad, who led one of the studies. “But their sources have remained a long-standing mystery. Our work definitively shows that FXTs can originate from the explosive death of a massive star. It also supports a causal link between GRB-supernovae and FXT-supernovae, in which GRBs are produced by successful jets, and FXTs are produced by trapped weak jets.”
Continue to the full Northwestern news article.