GRB260809A detected by Einstein Probe WXT, z=3.07 from VLT/X-shooter

AI Summary

The Einstein Probe Wide-field X-ray Telescope (WXT) detected GRB260809A, which lasted 34 seconds with an unabsorbed flux of 3.32 × 10^-9 erg s^-1 cm^-2. Subsequent observations revealed an optical counterpart with a spectroscopic redshift of z = 3.07.

Measurements

Notices (1)

Einstein Probe WXT — GRB · Sun, 09 Aug 2026 00:38:56 GMT

GCN Circulars (7)

GCN-45349 — EP260809a · Mon, 10 Aug 2026 17:01:42 GMT
The optical counterpart of the event EP260809a was observed using the ESO VLT UT3 telescope with the X-shooter spectrograph, revealing a spectroscopic redshift of z = 3.07 and a magnitude of r = 22.44. The spectrum showed strong absorption features consistent with Lyman-alpha at this redshift, along with various metal lines and H_2 Lyman-Werner band lines.

GCN-45335 — EP260809a · Sun, 09 Aug 2026 22:10:21 GMT
A team of astronomers observed the field of EP260809a using the Palomar 1-m telescope equipped with the WINTER camera but did not detect the optical counterpart. They established a 5-sigma upper limit of J = 19.37 mag (AB) in the near-infrared J band.

GCN-45332 — EP260809a · Sun, 09 Aug 2026 17:58:56 GMT
The fast X-ray transient EP260809a was detected by the Einstein Probe mission's Wide-field X-ray Telescope (WXT) and followed up by the Follow-up X-ray Telescope (FXT). The event lasted 34 seconds and was analyzed to have a photon index of 1.74 and an unabsorbed flux of 3.32 × 10^-9 erg s^-1 cm^-2 in the 0.5–4 keV range. The FXT detected an uncatalogued source with a photon index of 2.00 and an unabsorbed flux of 1.27 × 10^-12 erg/s/cm^2 in the 0.5-10 keV range.

GCN-45326 — EP260809a · Sun, 09 Aug 2026 07:27:51 GMT
The COLIBRÍ telescope detected the optical counterpart of EP260809a with a preliminary magnitude of z = 22.04 +/- 0.19, approximately 4.683 to 5.172 hours after the trigger, using the DDRAGO two-channel wide-field imager.

GCN-45325 — EP260809a · Sun, 09 Aug 2026 05:04:21 GMT
An optical counterpart to the event EP260809a, detected by EP, was marginally observed using an LCO 1m telescope at the Teide Observatory. The optical counterpart had a brightness of approximately r = 22, measured 3.36 hours after the trigger, and was calibrated with Pan-STARRS DR2 stars.

GCN-45324 — EP260809a · Sun, 09 Aug 2026 03:43:07 GMT
Astronomers detected an optical transient object at coordinates RA 21:54:19.2, DEC +17:36:23 with a preliminary magnitude of 21.53 in the r-band using the T193cm telescope at Observatoire de Haute-Provence. The observation was part of a follow-up to the EP260809a event, with data collected approximately 1.4 to 2.3 hours after the initial trigger.

GCN-45321 — EP260809a · Sun, 09 Aug 2026 02:46:04 GMT
The Einstein Probe (EP) mission detected an X-ray transient designated EP260809a using the Wide-field X-ray Telescope (WXT). A follow-up observation with the Follow-up X-ray Telescope (FXT) confirmed an uncatalogued X-ray source within the WXT error circle, with coordinates R.A. = 328.5816 deg, DEC = 17.6072 deg (J2000).