GRB 251124A

General information

EP251124a was reported as an Einstein Probe (EP/WXT) soft X-ray transient, but later refined analysis associated it with the known galaxy cluster AWM 7 rather than a new GRB-like counterpart. Numerous follow-up observations (X-ray and optical) reported no convincing new fading transient.

Wavelength coverage

• Gamma-rays: Fermi/GBM reported a long GRB (GRB 251124a) with a GBM localization (separate reporting stream).
• X-rays: EP/WXT triggered and EP/FXT provided onboard follow-up positions; Swift/XRT observed the field and reported uncatalogued sources with no evidence for fading in a cluster-dominated field.
• Optical/NIR: Multiple facilities (GIT, Kinder/SLT, NOT, Pan-STARRS1, GWAC, MASTER, Mondy/AZT-33IK) reported only upper limits in g/r/i/z/R/clear bands. Bands with no observations mentioned: UV, radio, sub-mm/mm, TeV.

Lightcurve and spectrum

• EP/WXT refined flux estimate: ~6.17e-11 erg/cm^2/s (band not specified in the circular).
• Swift/XRT (0.3–10 keV, observed): Source 6 mean flux 8.9e-13 erg/cm^2/s; a spectral fit is reported with Gamma1.87 and NH1.20e21 cm^-2 for Source 6, and Gamma5.93 with NH~2.22e22 cm^-2 for Source 2.
• Swift/XRT reports no evidence for fading for the listed uncatalogued sources.

Redshift

What’s special vs typical

• The EP trigger was later associated with the known galaxy cluster AWM 7, suggesting the alert may not correspond to a new GRB counterpart (a ‘known-source/cluster’ origin is atypical for a GRB-labeled event).