Measurements of the production of jets in association with a W or Z boson with the ATLAS detector

The production of jets in association with vector bosons is an important process to study QCD in a multi-scale environment at the LHC. The ATLAS collaboration has performed a first measurement of Z+jets cross sections in 85~pb$^{-1}$ of proton -- proton collision data taken in 2015 at centre-of-mass energies of 13~TeV. In data corresponding to 4.6~fb$^{-1}$ at a centre-of-mass energy of 7~TeV, the collaboration has measured the production of W+jets events and the cross section ratio of W+jets and Z+jets events. The measurements are compared to state-of-the-art QCD calculations and Monte Carlo simulations.