The discovery of ultra-diffuse galaxies (UDGs) that lack dark matter (DM) around NGC1052 has challenged the foundation of modern theory of galaxy formation, namely that galaxies are formed within DM halos. Without resorting to exotic solutions beyond the framework of ΛCDM, a plausible explanation is the so-called “mini-Bullet cluster collision” scenario, which posits that a high-speed collision between two gas-rich dwarfs near NGC1052 some 8 Gyr ago caused gas to dissipate and create stellar systems that we see today as UDGs, while the DM and some stars in the progenitor dwarf galaxies continue to move along their trajectories, and became possibly the most DM-dominant systems around NGC1052. Under the assumption that some old stars remain associated with these DM halos, we propose to search for planetary nebulae (PNe) toward NGC1052 with the NB506 and g-band filters of Hyper Suprime-Cam, which is the best, if not the only, way to detect the remnant DM halos from the collision. The PNe associated with the DM-less UDGs around NGC1052 can further be used to determine the distance to these galaxies, serving as an independent check for their DM content.
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