Where are the Cascades from Blazar Jets? An Emerging Tension in the $\gamma$-ray sky

Carlos Blanco, Oindrila Ghosh, Sunniva Jacobsen +1

Blazars are among the most powerful accelerators and are expected to produce a bright TeV $\gamma$-ray flux. However, TeV $\gamma$-rays are attenuated by interactions with intergalactic radi…