Speaker
Description
X-ray observations are a keystone in the study of active galactic nuclei (AGN), revealing variability in sources such as blazars, where emissions predominantly follow a power-law model and originate from relativistic jets directed towards Earth. In this contribution, we focused on a candidate neutrino-emitting blazar, for which observations from XMM-Newton, NuSTAR, Swift-XRT, and eROSITA are available in multiple epochs. This blazar exhibits properties similar to those of a changing-look AGN, typical for Seyfert galaxies. The X-ray spectra reveal variability in the $0.3-10$ keV band flux. During high flux states, the spectra follow the expected power-law model, consistent with the jet emission. In contrast, in lower flux states, the spectrum shows evidence of an additional component, resembling characteristics typically observed in Seyfert galaxies. In this work, we tested a variety of spectral models of increasing complexity to address the origin of this spectral change. The final results suggest that the origin of this extra component may be explained by coronal emission and photoionized absorption or reflection. This transition between the two spectral properties suggests the first-time detection of an X-ray changing-look blazar, opening new perspectives in the physics of neutrino emissions in blazars.
