Detection of enhanced very-high-energy gamma-ray emission from Markarian 421

Thomas Tavernier (on behalf of SST-1M Consortium), 15. 3. 2024

We report a significant increase in gamma-ray flux from Markarian 421 above 2 TeV. This observation was conducted through stereo observations using the 2 SST-1M IACTs currently in commissioning at the Ondrejov Observatory.

The observations extends from 13 March 2024 20:53 to 00:20 UTC resulting in a livetime of approximately 3.3 hours, during which a detection significance of 6.8 sigma was achieved with notable excess up to 7 TeV.

The observed flux from Markarian 421 reached levels typically observed from the Crab Nebula, suggesting a substantial increase compared to our previous baseline. Preliminary analysis yields a measured spectral index above 2 TeV of 3.4 ± 0.5 (stat).

Observations on Markarian 421 will continue during subsequent nights, depending on weather conditions. Multi-wavelength observations are encouraged.

The SST1M instrument is a pair of small-sized IACTs designed to detect gamma rays in the energy range of 1 to 300 TeV [1]. It is the product of a collaboration between institutions across Poland, Switzerland and The Czech Republic.

[ Read the original ATel #16533 … ]

[ Read the related ATel #16537 … ]
Detection of Very high energy gamma-ray flare from the blazar Mrk 421 with MACE
K K Yadav on behalf of MACE team (Bhabha Atomic Research Centre, Mumbai, India), 18. 3. 2024