X-ray transient EP260727a detected with Einstein Probe WXT, confirmed with optical counterparts

AI Summary

An X-ray transient was detected by the Einstein Probe WXT on 2026-07-27, followed by optical detections in multiple bands indicating a redshift of 1.03 and confirming the source's nature.

Measurements

Notices (1)

Einstein Probe WXT — GRB · Mon, 27 Jul 2026 20:37:57 GMT

GCN Circulars (7)

GCN-45245 — EP260727a · Tue, 28 Jul 2026 19:45:10 GMT
The 1.5m telescope at Sierra Nevada Observatory detected an optical counterpart to the event EP260727a in the Ic-band, confirming previous detections in the r and z-bands. The measured magnitude was 21.76, and further monitoring is ongoing.

GCN-45244 — EP260727a · Tue, 28 Jul 2026 15:59:03 GMT
The fast X-ray transient EP260727a was detected by the Einstein Probe's Wide-field X-ray Telescope (WXT) and followed up by several optical telescopes, with a refined analysis indicating a duration of about 70 seconds and a redshift of 1.03. The Follow-up X-ray Telescope (FXT) detected an uncatalogued source approximately 50 minutes later, providing further spectral and flux data.

GCN-45243 — EP260727a · Tue, 28 Jul 2026 13:56:48 GMT
Observations of the field EP260727a using the T193cm telescope at Observatoire de Haute-Provence detected two potential optical counterparts. The first counterpart is consistent with previous detections and has a preliminary magnitude of r = 22.82 +/- 0.28 mag, while the second counterpart, not present in PanStarrs images, has a preliminary magnitude of r = 20.49 +/- 0.06 mag.

GCN-45239 — EP260727a · Tue, 28 Jul 2026 10:23:11 GMT
The Liverpool Telescope confirmed an optical counterpart to the fast X-ray transient EP260727a, detecting it in the z band with a magnitude of 21.66, which is significantly brighter than the historical magnitude of the underlying source. The source was not detected in the r band, with an upper limit of 22.85, preventing an assessment of its fading.

GCN-45238 — EP260727a · Tue, 28 Jul 2026 09:23:05 GMT
The NUTTELA-TAO telescope observed the location of EP 260727a starting 1.05 hours after the initial trigger but did not detect any optical source consistent with the previously reported NOT optical counterpart. The observations were conducted in Sloan g' and i' bands, with 5 sigma upper limit sensitivities of 20.3 and 19.75 magnitudes respectively.

GCN-45235 — EP260727a · Tue, 28 Jul 2026 02:19:44 GMT
The Einstein Probe (EP) mission detected an X-ray transient, designated EP260727a, using its 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, consistent with a potential optical counterpart.

GCN-45234 — EP260727a · Tue, 28 Jul 2026 01:53:54 GMT
A brightened source with a magnitude of 21.98 in the r-band was detected within the error circle of the EP-WXT trigger ID 01709276927 using the Nordic Optical Telescope, suggesting it is likely the optical counterpart. The source was observed 3.69 hours post-burst and was also present in Legacy Survey DR10 images, indicating it may not be a new transient.