The Peculiar Variable X-Ray Spectrum of the Active Galactic Nucleus PKS 2005–489

Abstract PKS 2005−489 is a well-known, bright southern BL Lac object that has been detected up to TeV energies. In low-flux state it exhibits the expected multiwavelength double-peaked spectrum in radio− γ -ray band. The high-flux shows extreme flux variations X-ray band with hardening as well peculiar curved feature spectrum. Thus far, only source exhibit such feature. To study variability further, we obtained first hard of Nuclear Spectroscopic Telescope Array. We compare quasi-simultaneous radio, optical, UV, soft and X-ray, data archival order its broadband behavior. find very consistent quiet spectral energy distribution, little variation shape or between 2012 2020 data. A possible explanation for flaring an additional component jet, possibly accelerated via magnetic reconnection, not co-spatial emission region.