Tidal Distortions in NGC1052-DF2 and NGC1052-DF4: Independent Evidence for a Lack of Dark Matter

Abstract Two ultra-diffuse galaxies in the same group, NGC1052-DF2 and NGC1052-DF4, have been found to little or no dark matter host unusually luminous globular cluster populations. Such low-mass diffuse objects a group environment are easily disrupted expected show evidence of tidal distortions. In this work, we present deep new imaging NGC1052 obtained with Dragonfly Telephoto Array, test hypothesis. We find that both strong position-angle twists significantly more elongated at their outskirts than interiors. The group’s central massive elliptical is most likely source these disturbances. observed distortions imply low total mass very close NGC1052. Considering constraints on galaxies’ relative distances, infer halo masses cannot be much greater stellar masses. Calculating pericenters from distortions, highly orbits, ratio pericenter present-day radius R peri / 0 ∼ 0.1 if matter–free 0.01 they normal halo. Our findings provide evidence, independent kinematic constraints, matter–deficient. Furthermore, similarity features NGC1052-DF4 strongly suggests arose comparable distances Appendix A, describe sbcontrast , robust method for determining surface brightness limits images.