Bar resilience to flybys in a cosmological framework
  It has been proposed that close interactions with satellite galaxies can
significantly perturb the morphology of the main galaxy. However, the dynamics
of an already formed bar following the interaction with the external
environment has not been studied in detail in a fully cosmological context. In
this work, analysing the cosmological zoom-in simulation Eris2k, we study the
effects that a very unequal-mass flyby crossing the stellar disc has on the
stability of the pre-existing bar. We characterize the evolution of the bar
strength and length showing that the perturbation exerted by the flyby shuffles
the orbits of stars for less than one Gyr. After this time, the bar shows a
remarkable resilience, reforming with properties comparable to those it had
before the interaction. Our work shows that close unequal-mass encounters, the
most frequent interactions occurring during the evolution of cosmic structures,
have (i) an overall minor impact on the global evolution of the bar in the long
term, still (ii) the effect is destructive and (iii) a very weak interaction is
sufficient to dismantle a strong bar leading to its "apparent death". As a
consequence, due to the non-negligible duration of the bar-less period, a
fraction of observed spiral galaxies classified as non-barred could be prone to
bar formation.
