Photon and Z (+ jet) production in lead-lead collisions with ATLAS

ATLAS results on the production of photons and $Z$ bosons are presented. Their production rates are found to scale with the number of binary collisions, as expected from QCD factorization at large transverse momentum. This makes them an ideal tool for probing the modifcation of jets which balance their transverse momentum. Despite the large differences in available statistics, both channels show a strong modification of the energy of the recoil jets, which increases with decreasing impact parameter.