GCN Circular 45817
GRB 261001A: GECAM-B observation of a likely long GRB
From: Xinghao Luo at IHEP
Issued: 2026-10-06 08:43 UTC
Type: GRB, Gamma-ray Transient
Why this event is posted: every one of the gamma-ray bursts is posted.
Xing-Hao Luo, Chen-Wei Wang, Ren-Yang Zhao, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:
GECAM-B was triggered on-ground by GRB 261001A, at 2026-10-01T12:52:04.950 UTC (denoted as T0).
According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 42 +/-1 s.
The GECAM-B light curve can be found here:
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).
Every one of the gamma-ray bursts GCN reports is posted here.
Relayed automatically from NASA's General Coordinates Network.
In plain words Routine
On 1 October 2026, a Chinese gamma-ray satellite called GECAM-B detected a burst of high-energy light, known as a gamma-ray burst. These bursts usually come from far outside our Galaxy, often from the collapse of a massive star. The burst came as several pulses and lasted about 42 seconds, which is why the team calls it a likely 'long' burst (one lasting more than about two seconds). The report gives no sky position, distance, or sign of a fading glow in X-ray, visible or radio light, so what exactly produced it is not yet known.
How unusual is it? This is a single detection of an ordinary long gamma-ray burst, a kind that Fermi and Swift together report a few hundred times a year. A measured distance or a bright afterglow found by other telescopes would make it notable.
Written by an AI model (claude-sonnet-5-5) from the official reports in this thread; last updated . It may contain mistakes: the reports themselves are the authority.
GRB 261001A — GRB, Gamma-ray Transient