Flat Circular Velocities on a Megaparsec Scale from the ΛCDM Model

A recent study using weak gravitational lensing reveals that there are some isolated galaxies with almost flat rotation curves at very large distances from the galactic centers. According to the authors of the study, this provides a strong challenge to the standard cold dark matter model, since the...

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Bibliographic Details
Main Authors: Antonino Del Popolo, Man Ho Chan
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/adcc1c
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Summary:A recent study using weak gravitational lensing reveals that there are some isolated galaxies with almost flat rotation curves at very large distances from the galactic centers. According to the authors of the study, this provides a strong challenge to the standard cold dark matter model, since the dark haloes are too small to explain their observations, especially for small stellar masses. In this article, we show that by improving their model, the virial radius is larger than their estimates. The Navarro–Frenk–White rotational curve, and especially the pseudo-isothermal one, are in agreement with their flat rotational curves, especially for the larger baryonic mass bins used by the authors.
ISSN:1538-4357