LHAASO-WCDA Detection of Strong TeV Flaring Activity from the Radio Galaxy NGC 1275
ATel #17957; Guangman Xiang (IHEP),Shicong Hu(IHEP), Min Zha (IHEP), Zhiguo Yao (IHEP), Jianeng Zhou (SHAO) and Yi Xing (SHAO) report on behalf of the LHAASO Collaboration
on 11 Aug 2026; 14:11 UT
Credential Certification: Guangman Xiang (gmxiang@ihep.ac.cn)
Subjects: Gamma Ray, TeV, VHE, AGN
We report the detection of very-high-energy (VHE, E > 100 GeV) gamma-ray emission from the radio galaxy NGC 1275 (3C 84,z = 0.017) with the Large High Altitude Air Shower Observatory (LHAASO) - Water Cherenkov Detector Array (WCDA).
Recent Fermi-LAT observations have revealed enhanced gamma-ray flaring activity from this object (ATel #17937, #17943), and the source is presently in an exceptionally bright optical state (ATel #17955).
The VHE flaring activity was detected by the LHAASO-WCDA real-time alert system. During the time window MJD 61261.81-61262.15, a preliminary analysis yields an excess at the radio position of NGC 1275 with TS = 74.7 (~7.8 sigma). The preliminary observed spectrum in the ~0.4-7.5 TeV range is well described by a power law with photon index 2.98 +/- 0.17 (statistical errors only), corresponding to an integral flux above 1 TeV of ~ 0.6 Crab units.
Given the current high flux state of NGC 1275 across the gamma-ray, VHE, and optical bands, multi-wavelength follow-up observations are strongly encouraged.
LHAASO is a multi-purpose Extensive Air Shower (EAS) array designed to detect air showers induced by gamma rays and cosmic rays from sub-TeV energies to above 1 PeV.
