Exploring the Satellite Systems of Bulge-Less Galaxies: Insights from TNG50

The stochastic nature of galaxy growth within the $\Lambda$CDM framework favors the formation of dynamically hot structures in the inner regions of galaxies, such as classical bulges. These structures may arise from early chaotic collapse or dynamical heating through galaxy-galaxy mergers. In this context, the existence of massive ($>10^{10}M_{\odot}$) disk galaxies with little or no bulge remains poorly understood. The specific formation pathways of these bulge-less disk galaxies shape not only their morphology but also the properties of their satellite populations. In this work, we use the cosmological hydrodynamical simulation TNG50-1 to analyze the distinct properties of the satellite populations of bulge-less galaxies and investigate how those properties are linked to their host morphology. Our analysis indicates that bulge-less galaxies tend to host fewer satellites than bulge-dominated galaxies and exhibit steeper luminosity functions. Moreover, their satellites display a preferential 3D alignment and are more centrally concentrated. These results suggest that the formation history of the host galaxy influences both the abundance and orbital properties of its satellite system.