Very high energy emission mechanism in the extreme blazar PGC 2402248

Abstract

ABSTRACT Extreme high-frequency peaked BL Lacs (EHBLs) are characterized by a synchrotron peak frequency exceeding 1017 Hz and a second peak that can be in the energy range of few GeVs to several TeVs. The Major Atmospheric Gamma Imaging Cherenkov Telescope (MAGIC) detected multi-TeV gamma-rays on 2018 April 19 for the first time from the EHBL PGC 2402248, which was simultaneously observed in multiwavelength by several other instruments. The broad-band spectral energy distribution of the source is conventionally modelled using the leptonic and the hadronic models. Due to the success of the photohadronic model in interpreting the enigmatic very high energy (VHE) flaring events from many high-energy blazars, we extend this model to explain the VHE events from PGC 2402248 observed by MAGIC telescopes and compare our results with other models. We conclude that the photohadronic fits are comparable and even fare better than most other models. Furthermore, we show that the spectrum is not hard and is in a low-emission state. The estimated bulk Lorentz factor for this flaring event is found to be ≲34.