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The dwarf galaxies comparable to the LMC and SMC, with stellar masses , are found in a diversity of environments and have long quenching timescales. We need to understand how this phenomenon is connected to the dwarfs’ halo properties and their locations in the large-scale structure of the universe. We study the star-formation rates of dwarfs in the TNG50 simulation of the IllustrisTNG project across different environments, focusing on field dwarfs in host halos with virial masses of , in contrast to dwarf satellites in hosts with . Our field dwarf sample is heterogeneous, consisting of primary (central) galaxies, with smaller numbers of secondaries and dwarf galaxies that are on backsplash orbits around massive galaxies. We study how the quenched fraction and star-formation histories depend on the dwarfs’ large-scale environment and find that only $\sim 1\%$of the most isolated dwarfs are quenched. The vast majority of the quenched field dwarfs are backsplash dwarfs located in the neighborhood of cluster-scale halos. We discover a two-halo galactic conformity signal that arises from the tendency of the quenched dwarfs, particularly the backsplash sample, to have a quenched massive galaxy as a neighbor. We attribute the low quenched fractions of the simulated LMC/SMC analogs in the field to the locations of their low-mass hosts in the sparse large-scale environment, which predominate over the relatively small number of backsplash and quenched primary dwarfs in denser environments. 

Abstract We study the effect of the Large Magellanic Cloud (LMC) on the dark matter (DM) distribution in the Solar neighborhood, utilizing the Auriga magneto-hydrodynamical simulations of Milky Way (MW) analogues that have an LMC-like system. We extract the local DM velocity distribution at different times during the orbit of the LMC around the MW in the simulations. As found in previous idealized simulations of the MW-LMC system, we find that the DM particles in the Solar neighborhood originating from the LMC analogue dominate the high speed tail of the local DM speed distribution. Furthermore, the native DM particles of the MW in the Solar region are boosted to higher speeds as a result of a response to the LMC's motion.We simulate the signals expected in near future xenon, germanium, and silicon direct detection experiments, considering DM interactions with target nuclei or electrons. We find that the presence of the LMC causes a considerable shift in the expected direct detection exclusion limits towards smaller cross sections and DM masses, with the effect being more prominent for low mass DM. Hence, our study shows, for the first time, that the LMC's influence on the local DM distribution is significant even in fully cosmological MW analogues.