The $\gamma$-ray sky seen at X-ray energies I. Searching for the connection between X-rays and $\gamma$-rays in Fermi BL Lac objects

E. J. Marchesini, A. Paggi, F. Massaro +4

BL Lac objects are an extreme type of active galactic nuclei (AGNs) that belong to the largest population of $\gamma$-ray sources: blazars. This class of AGNs shows a double-bumped spec…