2025A&A...699A.285T

Context. Some galaxies such as the Milky Way and Andromeda display coherently rotating satellite planes, posing tensions with cosmological simulations. NGC 2750 has emerged as an additional candidate system hosting a co-rotating group of galaxies.
Aims. This work aims to verify the presence of a coherent plane of satellites around NGC 2750 by identifying new candidate dwarf galaxies and low surface brightness features.
Methods. We conducted deep photometric observations of NGC 2750 and its surroundings over an area of ∼35'×30' using the Large Binocular Telescope (LBT) in the g- and r-bands. Standard data reduction techniques were employed to improve the detection of low-surface-brightness-features down to a depth of μ_r∼31 mag arcsec^–2. We analysed the morphology of NGC 2750 and other galaxies in this system for signs of tidal interactions and performed structural and photometric analyses of recently identified candidate satellites.
Results. Our observations led to the discovery of six new candidate dwarf galaxies, one of which exhibits properties consistent with an ultra-diffuse galaxy. We identified tidal features around NGC 2750, suggesting past interactions with its neighbouring satellites. While the spatial distribution of satellites suggests a moderate flattening, and this flattening is supported by the new candidates, follow-up spectroscopic measurements of the new candidates have the potential to bolster or diminish the strong kinematic coherence observed previously. The luminosity function of NGC 2750 shows an excess of bright satellites compared to similar systems, contributing to the growing evidence of discrepancies between observed satellite distributions and predictions from cosmological simulations.