Plate Nº 25 · recorded October 13, 2026
Space & AstronomyReported finding
Gamma-ray burst's engine fired for 27 days, shattering the record
Astronomers tracked GRB 220706A's central engine for 27.25 rest-frame days after its July 2022 detection, beating the prior record by 20 days. The burst may also be the first confirmed pairing with a superluminous supernova.
By Elena Vasquez3 min read575 words
In brief
- GRB 220706A's central engine stayed active for 27.25 rest-frame days, about 20 days longer than the previous record.
- The burst was first detected on July 6, 2022, at a redshift of z = 0.8577.
- It ranks 8th longest among 549 gamma-ray bursts analyzed, with an initial flash of about 15.6 hours.
- X-ray flares continued for roughly 51 days in Earth's frame before the redshift correction.
- If confirmed, the associated supernova would mark the first superluminous supernova seen alongside a gamma-ray burst.
A gamma-ray burst spotted in July 2022 kept its central engine blazing for 27.25 rest-frame days, roughly 20 days longer than any previously recorded burst. The record belongs to GRB 220706A, first detected on July 6, 2022, by NASA's Swift satellite.
The team behind the find is led by Benjamin P. Gompertz of the University of Birmingham. The paper posted to the arXiv preprint server on Sept. 18, 2026. Data came from Swift's X-ray Telescope, NASA's NICER and the Chandra X-ray Observatory, four ground-based optical and infrared telescopes, plus the NOEMA array in France and the Karl G. Jansky Very Large Array in New Mexico. Follow-up stretched from about 100 seconds after the blast to Oct. 5, 2023.
What did the burst actually do?
GRB 220706A ranks eighth-longest among 549 gamma-ray bursts the team analyzed. Its initial flash ran about 15.6 hours, longer than the so-called "archetypal" ultra-long bursts. X-ray telescopes then caught repeated flares for another 51 days in Earth's frame.
The light had to cross a vast, expanding universe. GRB 220706A sits at a redshift of z = 0.8577. That distance stretches the time between signals. Correct for redshift, and the last flare lands at 27.25 rest-frame days.
"Corrected for redshift, this last epoch of flaring suggests that the central engine of GRB 220706A is still active at 27.25 rest-frame days after trigger," the team writes. The previous record-holder, GRB 210204A, only managed about 6.6 rest-frame days of delayed flaring.
Why was the optical light so faint?
The X-rays blazed. The optical light barely showed. That mismatch makes GRB 220706A a "dark burst." The team's paper points to dust in the host galaxy: "One likely explanation is substantial dust extinction within the host galaxy, which potentially obscures the afterglow emission."
Dust dims visible afterglow while leaving X-rays mostly alone.
Is there a supernova in the mix?
About 17 days after the burst, an extra bump of optical light appeared. Its timing matched predictions for a supernova. Adjust for dust, and the explosion looks unusually bright. It may be a "superluminous" supernova, a much rarer category.
If confirmed, this would be the first known pairing of a gamma-ray burst and a superluminous supernova in the same event.
What could be powering the engine?
The team tested three main ideas. None fit perfectly.
- A collapsing massive star feeding a black hole is plausible, though it strains current models.
- A newborn magnetar, a city-sized neutron star with a fierce magnetic field, matches some ultra-long bursts, but the timescales may be off. The team notes: "the typical timescales of such flares are of the order of seconds to minutes, and nascent magnetars are not expected to have fully formed crusts at timescales relevant to GRB 220706A."
- A tidal disruption event, a star shredded by a black hole, fits the burst's location near its galaxy's center, but the X-ray and optical behavior looked more like a standard long GRB.
The team ultimately favored a collapsing star paired with a supernova, citing similarities to a confirmed case. Still, the extra optical light could simply be an odd flare mimic, not a supernova at all.
Ultra-long gamma-ray bursts remain rare. GRB 220706A now sets a new bar for how long these engines can keep firing.
via Phys.org Space & Astronomy (Source)
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Correspondent covering money, funding and market shifts around general science news at SciBeat.
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