Flat Central Density Profile and Constant DM Surface Density in Galaxies
  from Scalar Field Dark Matter
  The scalar field dark matter (SFDM) model proposes that galaxies form by
condensation of a scalar field (SF) very early in the universe forming
Bose-Einstein Condensates (BEC) drops, i.e., in this model haloes of galaxies
are gigantic drops of SF. Here big structures form like in the LCDM model, by
hierarchy, thus all the predictions of the LCDM model at big scales are
reproduced by SFDM. This model predicts that all galaxies must be very similar
and exist for bigger redshifts than in the LCDM model. In this work we show
that BEC dark matter haloes fit high-resolution rotation curves of a sample of
thirteen low surface brightness galaxies. We compare our fits to those obtained
using a Navarro-Frenk-White and Pseudo-Isothermal (PI) profiles and found a
better agreement with the SFDM and PI profiles. The mean value of the
logarithmic inner density slopes is -0.27 +/- 0.18. As a second result we find
a natural way to define the core radius with the advantage of being
model-independent. Using this new definition in the BEC density profile we find
that the recent observation of the constant dark matter central surface density
can be reproduced. We conclude that in light of the difficulties that the
standard model is currently facing the SFDM model can be a worthy alternative
to keep exploring further.
