Bibcode
                                    
                            Gannon, Jonah S.; Buzzo, Maria Luisa; Ferré-Mateu, Anna; Forbes, Duncan A.; Brodie, Jean P.; Romanowsky, Aaron J.
    Bibliographical reference
                                    Monthly Notices of the Royal Astronomical Society
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                        9
            
                        2023
            
  Citations
                                    7
                            Refereed citations
                                    7
                            Description
                                    In this study, we use Keck/Keck Cosmic Web Imager spectroscopy to measure the age, metallicity, and recessional velocity of NGC 1052-DF9 (DF9), a dwarf galaxy in the NGC 1052 group. We compare these properties to those of two other galaxies in the group, NGC 1052-DF2 and NGC 1052-DF4, which have low dark matter content. The three galaxies are proposed constituents of a trail of galaxies recently hypothesized to have formed as part of a 'bullet dwarf' collision. We show that the ages and total metallicities of the three galaxies are within uncertainties of one another which may be expected if they share a related formation pathway. However, the recessional velocity we recover for DF9 (1680 ± 10 km s-1) is higher than predicted for a linearly projected interpretation of the 'bullet dwarf' trail. DF9 is then either not part of the trail or the correlation of galaxy velocities along the trail is not linear in 2D projection due to their 3D geometry. After examining other proposed formation pathways for the galaxies, none provide a wholly satisfactory explanation for all of their known properties. We conclude further work is required to understand the formation of this interesting group of galaxies.
                            Related projects
                 
Traces of Galaxy Formation: Stellar populations, Dynamics and Morphology
            
    We are a large, diverse, and very active research group aiming to provide a comprehensive picture for the formation of galaxies in the Universe. Rooted in detailed stellar population analysis, we are constantly exploring and developing new tools and ideas to understand how galaxies came to be what we now observe.
            
            Anna
            
                        Ferré Mateu