Temporal and Spectral Study of Markarian 421’s Activity States Using HAWC Data

The High-Altitude Water Cherenkov (HAWC) observatory, located in Volcán Sierra Negra, México, is designed to detect very high-energy (VHE) gamma rays and has provided continuous sky observations in the range of hundreds of GeV to hundreds of TeV since it began operations in 2015. Over nine years (2015–2024), HAWC has revealed the evolution of the light curve of the blazar Markarian 421 (Mrk 421), including both low- and high-activity states. The main motivation for this study is the series of flares detected during this period, which remain largely unexplored in detail. These events provide a unique opportunity to investigate the physical processes taking place during extreme activity states in blazars. In this context, we present a temporal spectral analysis of Mrk 421 during its active phase between 2017 and 2018. During this flare, the flux reached levels up to four times higher than the average quiescent state.