The global warming of group satellite galaxies

Recent studies adopting λ_Re, a proxy for specific angular momentum, have highlighted how early-type galaxies (ETGs) are composed of two kinematical classes for which distinct formation mechanisms can be inferred. With upcoming surveys expected to obtain λ_Re from a broad range of environments (e.g. SAMI, MaNGA), we investigate in this numerical study how the λ_Re-ɛ_e distribution of fast-rotating dwarf satellite galaxies reflects their evolutionary state. By combining N-body/SPH simulations of progenitor disc galaxies (stellar mass ≃10⁹ M_⊙), their cosmologically-motivated sub-halo infall history and a characteristic group orbit/potential, we demonstrate the evolution of a satellite ETG population driven by tidal interactions (e.g. harassment). As a general result, these satellites remain intrinsically fast-rotating oblate stellar systems since their infall as early as z = 2; mis-identifications as slow rotators often arise due to a bar/spiral lifecycle which plays an integral role in their evolution. Despite the idealistic nature of its construction, our mock λ_Re-ɛ_e distribution at z < 0.1 reproduces its observational counterpart from the ATLAS^3D/SAURON projects. We predict therefore how the observed λ_Re-ɛ_e distribution of a group evolves according to these ensemble tidal interactions.