Estimation of dark matter content in dark matter deficient galaxies

Abstract

The recent discoveries of several dark matter deficient galaxies pose a severe challenge to the current understanding of galaxy formation and evolution. The existence of such galaxies demands either an extra-ordinary efficiency of galaxy formation or a highly ef fective mechanism of dark matter removal from galaxies. Numerical studies, however, suggest that it is possible to produce these galaxies in dense environments during the early epoch of galaxy formation where the dark matter could be stripped e↵ectively through tidal interactions.However, recent observations of Guo et al. (2019) identified 14 dark matter deficient galaxies in the field, which is the first such large sample of such galaxies. Guo et al. (2019) used single-dish HI observations to identifythese galaxies from the ALFALFA survey. However, the single-dish measurements have critical shortcomings as they cannot resolve the HI distribution in the galaxies and instead used global HI profiles to extract kinematic information. Moreover, due to the lack of resolved velocity fields, they could not produce the rotation curves and mass-modeling, which is vital in confirming dark matter deficiency.