Are Milky-Way dwarf-spheroidal galaxies dark-matter free?
Abstract
We have found that the high velocity dispersions of dwarf spheroidal galaxies (dSphs) can be well explained by Milky Way (MW) tidal shocks, which reproduce precisely the gravitational acceleration previously attributed to dark matter (DM). Here we summarize the main results of Hammer et al. (2019) who studied the main scaling relations of dSphs and show how dark-matter free galaxies in departure from equilibrium reproduce them well, while they appear to be challenging for the DM model. These results are consistent with our most recent knowledge about dSph past histories, including their orbits, their past star formation history and their progenitors, which are likely tiny dwarf irregular galaxies.
Keywords
Cite
@article{arxiv.1909.07979,
title = {Are Milky-Way dwarf-spheroidal galaxies dark-matter free?},
author = {F. Hammer and Y. B. Yang and J. L. Wang and F. Arenou and C. Babusiaux and M. Puech and H. Flores},
journal= {arXiv preprint arXiv:1909.07979},
year = {2019}
}
Comments
4 pages, 2 Figs., in the Conference of the French Society of Astronomy and Astrophysics (SF2A 2019, Nice); for more informations (and for an accompanying video) see the final (ApJ accepted) version of Hammer et al. 2019 (arXiv:1812.10714), which main results are summarized here, v2: it includes a small correction in Figure 1 (about Sofue, 2015 rotation curve)