Brownian Motion of Dark Matter

Hsi-Yu Schive^1,2*, Tzihong Chiueh^1,2, Tom Broadhurst³

¹Graduate Institute of Astrophysics, National Taiwan University, Taipei, Taiwan
²Center for Theoretical Physics, National Taiwan University, Taipei, Taiwan
³Department of Theoretical Physics, University of the Basque Country UPV/EHU, Bilbao, Spain

* Presenter:Hsi-Yu Schive, email:hyschive@phys.ntu.edu.tw

Fuzzy dark matter exhibits rich wave-like structure, including a soliton core within a surrounding halo that continuously self-interferes on the de Broglie scale. In this talk, I will address the soliton random walk at the base of the halo potential. This is significant for the fate of the ancient central star cluster in Eridanus II, as the agitated soliton gravitationally shakes the star cluster in and out of the soliton that leads to complete tidal disruption of the star cluster within ~1 Gyr. This destructive effect can be mitigated by tidal stripping of the halo of Eridanus II, thereby reducing the agitation. Our simulations show the Milky Way tide has a stronger effect on the halo than the soliton, so the star cluster in Eridanus II can survive for over 5 Gyr within the soliton if it formed after significant halo stripping.

Keywords: Dark matter, Soliton, Brownian motion, Star cluster, Simulation