Year: 2025
Type: conference-paper
Abstract: This talk presents a comprehensive study of Mrk 421 using three years of observations from the LHAASO-WCDA detector, spanning from March 2021 to March 2024 in the energy range of 0.4–13 TeV. Benefiting from the detector’s continuous and unbiased monitoring capabilities, we construct a continuous light curve sampled at a daily cadence and identify 23 very-high-energy (VHE) flaring episodes using the Bayesian Blocks algorithm. The durations of these flares vary widely, ranging from sub-day timescales to several weeks, with the most intense reaching up to 3.3 Crab Unit. Spectral analysis shows that all flares can be well described by a power-law model, with the photon index exhibiting a “harder-when-brighter” trend. The flaring duty cycle is calculated to be approximately 14.6%, depending on the flux threshold. In addition, long-term averaged spectra are extracted for each year, and spectral fits with EBL absorption correction indicate significant inter-annual variability in both flux normalization and cutoff energy. These results highlight the capability of LHAASO for long-term TeV-band blazar monitoring and provide valuable insight into the high-energy emission behavior of Mrk 421.
DOI: 10.22323/1.501.0897
Authors: Min Zha, Z.G. Yao, L. Cheng, J. N. Zhou, Y. Xing, S. C. Hu, G.M. Xiang, Y. Huang
Institutions: Chinese Academy of Sciences, Institute of High Energy Physics
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W4415119211
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