Dark matter self-interactions from the internal dynamics of dwarf spheroidals. (November 2018)

• Record Type: Journal Article
• Authors: Valli, Mauro; Yu, Hai-Bo
• Is Part Of: Nature astronomy. Volume 2:Number 11(2018)
• Page Start: 907
• Page End: 912
• Publication Date: 2018-11
• Subjects: Astronomy -- Periodicals; 520.5
• DOI: 10.1038/s41550-018-0560-7
• Languages: English
• ISSNs: 2397-3366

Abstract

Abstract Dwarf spheroidal galaxies provide well-known challenges to the standard cold and collisionless dark matter scenario1, 2 : the too-big-to-fail problem (namely the mismatch between the observed mass enclosed within their half-light radius3, 4 and cold dark matterN -body predictions5, 6 ) and the hints for inner constant-density cores7–10 . While these controversies may be alleviated by baryonic physics and environmental effects11–15, revisiting the standard lore of cold and collisionless dark matter remains an intriguing possibility. Self-interacting dark matter16, 17 may be the successful proposal to such a small-scale crisis18, 19 . Self-interactions correlate dark matter and baryon distributions, allowing for constant-density cores in low-surface-brightness galaxies20–23 . Here, we perform a data-driven study of the too-big-to-fail problem of Milky Way dwarf spheroidals within the self-interacting dark matter paradigm. We find a good description of their stellar kinematics and compatibility with the concentration–mass relation from the pure cold dark matter simulation in ref.24 . Within this concentration–mass relation, a subset of Milky Way dwarfs are well fitted by cross-sections of 0.5–3.0 cm2 g−1, while others point to values greater than 10 cm2 g−1 . A data-driven study of the too-big-to-fail problem of Milky Way dwarf spheroidals within the self-interacting dark matter paradigm finds a good description of their stellar kinematics and compatibility with the concentration–mass relation of pure cold dark matter simulations.