2018/10/31 by David J. E. Marsh, Jens C. Niemeyer · 2 citations
Physics and Astronomy · #astro-ph.CO #astro-ph.GA #hep-ph
paper · pdf · doi:10.1103/physrevlett.123.051103
published as Phys. Rev. Lett. 123, 051103 (2019) · 6 pages, 2 figures; v2 comments and clarifications added, matches version accepted for publication in PRL
arxiv created 2019/07/30 · arxiv updated 2019/08/07
The fuzzy dark matter (FDM) model treats DM as a bosonic field with astrophysically large de Broglie wavelength. A striking feature of this model is O(1) fluctuations in the dark matter density on time scales which are shorter than the gravitational timescale. Including for the first time the effect of core oscillations, we demonstrate how such fluctuations lead to heating of star clusters, and thus an increase in their size over time. From the survival of the old star cluster in Eridanus II we infer ma\gtrsim 0.6→ 1× 10-19 eV within modelling uncertainty if FDM is to compose all of the DM, and derive constraints on the FDM fraction at lower masses. The subhalo mass function in the Milky Way implies ma\gtrsim 0.8× 10-21 eV to successfully form Eridanus II. The window between 10-21 eV\lesssim ma\lesssim 10-20 eV is affected by narrow band resonances, and the limited applicability of the diffusion approximation. Some of this window may be consistent with observations of Eridanus II and more detailed investigations are required.