Extreme High Frequency BL Lac Objects (EHBLs) at Very High Energies

Blazars are a class of active galactic nuclei (AGN) where the relativistic jet is pointed towards the line of sight of the observer. They are powerful sources of non-thermal radiation from radio to very high energy (VHE) gamma rays. The corresponding broadband spectral energy distribution shows two broad components : the lower energy component is located in the optical-to-X-ray band while the high energy component peaks in the gamma-ray band. BL Lac objects are further classified into Low frequency peaked BL Lacs (LBLs), intermediate frequency peaked BL Lacs (IBLs) and High-frequency peaked BL Lacs (HBLs) depending on the position of the synchrotron peak of their spectra. Extreme high-frequency BL Lac (EHBLs) objects show a synchrotron peak frequency above 10^17 Hz. After a short introduction on EHBLs and their characteristcs, in this talk, I will discuss the recent multiwavelength campaign carried out (over a period of 3 years between 2019 and 2021) on an intermittent extreme HBL 1ES2344+514. which includes near-simultaneous observations ( very high energy gamma-ray observations using MAGIC, high energy gamma rays Fermi-LAT, X-rays using XMM-Newton, NuSTAR and Astrosat and optical involving several optical telescopes around the world) in order to get a better understanding of the source.