http://arxiv.org/abs/1801.00565
There has been considerable interest in the last several years in support of the idea that galaxies and clusters could have highly condensed cores of dark matter within their central regions. In particular, it has been suggested that dark matter could form Bose–Einstein condensates (BECs) or degenerate Fermi cores. We examine these possibilities under the assumption that the core consists of highly condensed dark matter (either bosons or fermions) that is embedded in an isothermal halo. The novelty of our approach is that we invoke composite polytropes to model spherical collisionless structures in a way that is physically intuitive and can be generalized to include other `equations of state’ (EOSs). We find that Bose–Einstein condensates admit solutions that are consistent with the observations for a wide range of particle masses, while the constraints imposed on the masses of fermions are much more stringent (1-1000 keV). Finally, we note that this approach can be extended to include a wide range of EOSs in addition to multi-component collisionless systems.
W. Chung and L. Nelson
Wed, 3 Jan 2018
37/59
Comments: 17 pages, 5 figures Original version submitted Dec.31/17 and replaced on Jan.2/17
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