Jet fragmentation and multijet studies in heavy ion collisions at ATLAS

We report on two measurements done by ATLAS in a context of exploring the jet quenching physics at LHC: the jet fragmentation measurement and the measurement of \nearby jet production. Both of these measurements were done using the data collected in 2011 Pb+Pb run providing Pb+Pb collisions at $\sqrt{s_{NN}} = 2.76~$TeV. These measurements are expected to provide an insight into the modifications of jets initiated by partons passing through hot and dense QCD matter created in heavy ion collisions.