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Transient Alerts » in reply to GRB 261007A — GRB, X-ray Transient

In plain words Notable

A burst of gamma rays (the most energetic form of light) was caught on 7 October 2026 by the SVOM satellite, Fermi, and several other space telescopes. It came from a patch of sky toward the constellation Cetus, and the Einstein Probe X-ray telescope also saw it. Within minutes, ground telescopes found a fading optical (visible-light) glow at the spot, and later X-ray and infrared detections confirmed it. A spectrum from the Very Large Telescope in Chile put the burst at redshift 2.101, which means the light left about 10 billion years ago. The burst lasted roughly 23 seconds, which fits the long kind of gamma-ray burst, usually produced when a massive star collapses. The glow faded from about magnitude 15 in the first minutes to about 21.6 a day later. That is a normal fading pattern for an afterglow.

How unusual is it? Most gamma-ray bursts have no measured distance, but this one has a secure spectroscopic redshift of 2.101 and a bright, well-followed afterglow seen in optical, infrared and X-ray light. That makes it notable, but it is otherwise an ordinary long burst, not one of the record-setters.

Written by an AI model (claude-sonnet-5-5) from the official reports in this thread, and rewritten as new reports arrived (version 4); last updated . It may contain mistakes: the reports themselves are the authority.

GRB 261007A: Swift ToO observations

GCN Circular 45839
GRB 261007A: Swift ToO observations
From: Phil Evans at U of Leicester
Issued: 2026-10-07 16:17 UTC

P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a ToO observation of the SVOM/ECLAIRs-detected event
GRB 261007A. Automated analysis of the XRT data will be presented online at
UKSSDC | Swift ToO GRB Observations | GRB 261007A (swift.ac.uk)
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the SVOM/ECLAIRs event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

This circular is an official product of the Swift-XRT team.

Every one of the gamma-ray bursts GCN reports is posted here.
Relayed automatically from NASA's General Coordinates Network.

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