Boson stars can be matched onto the observational constraints for galactic dark matter halos [145, 199]. However, multi-state boson stars that superpose various boson-star solutions (e.g., an unexcited solution with an excited solution) can perhaps find better fits to the constraints [215]. Boson stars at the galactic scale may not exhibit general relativistic effects and can be effectively considered as Bose–Einstein condensates (BEC) with angular momentum [185].
The solitonic nature of boson stars (see Figure 1) lends itself naturally to the wonderful observation of
dark matter in the Bullet Cluster [146]. Ref. [144] attempts to determine a minimum galactic mass from
such a match.
Interestingly, Ref. [19] foregoes boson stars and instead looks for quasi-stationary scalar solutions about a Schwarzschild black hole that could conceivably survive for cosmological times. Another approach is to use scalar fields for both the dark matter halo and the supermassive, central object. Ref. [8] looks for such a match, but finds no suitable solutions. Quite a number of more exotic models viably fit within current constraints, including those using Q-balls [71].
http://www.livingreviews.org/lrr-2012-6 |
Living Rev. Relativity 15, (2012), 6
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