Astronomers have long puzzled over the source of mysterious X-ray flashes, or fast-X-ray transients (FXTs), which have been detected in distant galaxies for decades. A new study has revealed that these bursts of X-radiation are caused by failed gamma-ray bursts (GRBs) from massive stars.
The study, published in The Astrophysical Journal Letters, used data from the Einstein Probe telescope to detect an FXT event occurring 2.8 billion light-years away. Researchers then analyzed the event using a suite of telescopes to record it across multiple wavelengths.
The team found that the FXT was associated with a supernova event, nicknamed “The Kangaroo,” which was a rare and energetic variety known as a Type Ic-BL supernova. The supernova originated from the core collapse of a massive star between 15 and 30 times the mass of the Sun.
Contrary to previous assumptions, the researchers discovered that the jets that erupted from the core of this dying star remained trapped inside the shell of ejecta, producing FXTs rather than GRBs. This “trapped” jet outcome is more common in massive star explosions than successful emergence.
The discovery sheds new light on the diversity of massive stars’ deaths and provides a means for probing supernova explosions. However, further investigations are needed to understand what makes a star sputter out an FXT rather than a GRB.
Source: https://www.sciencealert.com/dying-stars-strangled-jets-solve-50-year-old-x-ray-mystery