ASTRI-1 detection of enhanced very high-energy gamma-ray emission from Mrk 421 at TeV energies
ATel #17602; S. Crestan (INAF/IASF Milano), C. Quartiroli (INAF/IASF Milano), A. Sunny (INAF/IAPS Roma), S. Lombardi (INAF/OAR Roma), F. Lucarelli (INAF/OAR Roma), F. Pintore (INAF/IASF Palermo), for the ASTRI Project
on 15 Jan 2026; 17:41 UT
Credential Certification: Fabio Pintore (fabio.pintore@inaf.it)
Subjects: Gamma Ray, TeV, VHE, AGN, Blazar
Referred to by ATel #: 17622
The ASTRI-1 telescope has observed an increase in the very high-energy gamma-ray flux from the blazar Mrk 421 (z = 0.031). Observations were performed between 2026/01/15 - 2:00 UTC (MJD 61055.08) and 04:40 UTC (MJD 61055.20) for a total effective observation time of approximately 2.5 hr. A preliminary analysis of the collected data reveals a significant detection of 11 sigma. The detected gamma-ray flux between 0.8 and 5 TeV is estimated to be 2.3 +/- 0.3 (stat) Crab Units.
This detection is consistent with the high level activity reported by LHAASO (ATel #17535), VERITAS (ATel #17594) and by SST-1M (ATel #17597).
Further ASTRI observations are planned to monitor Mrk 421. The ASTRI contact persons are Giovanni Pareschi (giovanni.pareschi@inaf.it) and Andrea Giuliani (andrea.giuliani@inaf.it). Multi-wavelength observations are encouraged.
ASTRI-1 is a dual-mirror, Schwarzschild-Couder, Imaging Atmospheric Cherenkov Telescope located at the Observatorio del Teide, Canary Islands (Spain), and it is the first telescope of the ASTRI Mini-Array Project, an international collaboration led by INAF (Italy). More information on the ASTRI Project can be found at the website http://www.astri.inaf.it .
