The standard cosmological paradigm produces galaxies lacking dark matter - Jorge Moreno

The standard cosmological paradigm produces galaxies lacking dark matter - Jorge Moreno

Desde Noviembre 23, 2021 03:21 hasta Noviembre 23, 2021 15:30

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The standard cosmological paradigm produces galaxies lacking dark matter

Jorge Moreno

University of Pomona

The standard cold dark matter plus cosmological constant model postulates that galaxies form within dark matter halos and predicts that low-mass galaxies are more dark-matter dominated than massive ones. The unexpected discovery of two low-mass galaxies lacking dark matter immediately provoked concerns about the standard cosmology, and ignited explorations of alternatives, including self-interacting dark matter and modified gravity. Apprehension grew after several simulations using the conventional cosmology failed to adequately form numerical analogs. Here we show, for the first time, that the standard paradigm naturally produces galaxies lacking dark matter, with characteristics largely in agreement with observations. Using FIREbox, a new cosmological simulation, we find that extreme close-encounters with massive neighbors can transform regular galaxies into dark-matter deficient ones. We predict that ? 15% of low-mass galaxies (with 10^8 ? 10^9 solar masses in stars) near massive neighbors (with at least 10^11 solar masses) are dark-matter deficient. This distinctive class of galaxies opens an additional layer to our understanding of the role of interactions in shaping galactic properties. Future observations surveying galaxies in the aforementioned regime will provide a crucial test of this scenario.