Observations from NASA’s Chandra X-ray Observatory, published Thursday in a study in Astrophysical Journal Letters, reveal how utterly unusual the aftermath of the event has been. The afterglow of the neutron star smashup in question has steadily brightened in recent months, and while researchers don’t have a concrete explanation for the change, they’ve got some pretty compelling ideas.
“Usually when we see a short gamma-ray burst, the jet emission generated gets bright for a short time as it smashes into the surrounding medium — then fades as the system stops injecting energy into the outflow,” the study’s co-author Daryl Haggard, an astrophysicist at McGill University, says in a statement. “This one is different; it’s definitely not a simple, plain-Jane narrow jet.”
The researchers have dubbed their leading hypothesis the “cocoon theory,” which, sadly, has nothing to do with caterpillar pods. According to this idea, the collision of the two neutron stars released so much energy that it triggered a jet — and a “cocoon” around it — that could glow in x-rays and radio light. That could explain the unusual observations from the Chandra X-ray Observatory.