Outer and inner mass distributions of the irregular galaxies UGC 4284
  and UGC 11861: Constraining the baryonic content through stellar population
  synthesis studies
  In this article we investigate the outer and inner mass distributions of the
irregular galaxies UGC 4284 and UGC 11861, taking advantage of published HI and
H{\alpha} high resolution rotation curves and constraining the stellar disk of
both galaxies throughout stellar population synthesis studies. In addition we
take into account the gas content of both galaxies deriving the HI+He rotation
curve. The deduced baryonic rotation curves (star+gas) are inadequate to
account for the total mass of UGC 4284 and UGC 11861, for that reason we
examine the possibility of dark matter to explain the incongruity between the
observed HI and H{\alpha} rotation curves of UGC 4284 and UGC 11861 and the
derived baryonic rotation curves. We consider NFW, Burkert, DiCintio, Einasto,
and the Stadel dark matter halos, to analyse the dark matter content of UGC
4284 and UGC 11861. The principal results of this work are that cored dark
matter models better reproduce the dark matter H{\alpha} and HI rotation curves
of UGC 11861 and the dark matter HI rotation curve of UGC 4284, while, the
H{\alpha} rotation curve of UGC 4284 is better reproduced by a cuspy DiCintio
DM model. In general, cored exponential two-parameters models Einasto and
Stadel, give better fits than Burkert. This trend, as well as to confirm past
results, presents for the first time a comparison between two different
exponential dark matter models, Einasto and Stadel, in an attempt to better
constrain the range of possible exponential dark matter models applied to real
galaxies.
