The collision, dubbed GW170817, was tracked back in 2017. Astronomers discovered an intense gamma-ray burst, considered one of the most energetic and brightest events in the Universe. Now, an intriguing glow is still radiating.
The recent discovery was interpreted as the result of a relativistic jet. And, as this jet moves into space, it produces its shockwave, emitting light across the spectrum, from radio waves to X-rays. Some astronomers, however, think otherwise. Here is what you need to know.
The Strangest Afterglow Ever Seen
This year in March, a team of astronomers used the Chandra X-ray Observatory to observe the strange glow. The discovery is astonishing.
The team found that the prolonged emission is still consistent with a relativistic jet. And as impressive as it might be, astronomers don’t know what enabled it to continue its activity.
Astronomer Eleonora Troja from the University of Maryland released a statement discussing the possible reasons. She said: “[…] there are physical processes we have not included in our models because they’re not relevant in the earlier stages that we are more familiar with when the jets form.”
The team considers another reason: it’s not the jet itself that triggered the extended emission, but an expanding cloud of gas from the kilonova that arose behind it, producing its shockwave. And if many shockwaves occur at various times and act differently, that could reveal how the diversity in how the multiple wavelengths faded.
Furthermore, the X-rays could have been extended by what the team called “continued energy injection by a long-lived central engine.”
Unfortunately, the astronomers don’t have enough data to find out which of those reasons triggered the continued glow. More investigation of the GW170817 will begin in December 2020, and the team is not really sure what it’s going to find, but optimism arises.
Either way, future discoveries, and research will help constrain the astronomers’ understanding of the unique event.