2017MNRAS.468..180R

In this work, we study the mass distribution of two irregular galaxies, UGC 6446 and UGC 7524, by means of H I rotation curves derived from high-resolution H I velocity fields obtained through the Westerbork Synthesis Radio Telescope data archive. We constrain the stellar and gas content of both galaxies with stellar population synthesis models and by deriving the H I+He+metals rotation curves from the total H I surface density maps, respectively. The discrepancy between the circular velocity maxima of the stellar plus the H I+He+metals rotation curves and the observed H I rotation curves of both galaxies requires the inclusion of a substantial amount of dark matter. We explore the Navarro Frenk and White, Burkert, Di Cintio, Einasto and Stadel dark matter halo models. We obtain acceptable fits to the observed H I rotation curves of UGC 6446 and UGC 7524 with the cored Burkert, Einasto and Stadel dark matter haloes. In particular, Einasto and Stadel models prove to be an appropriate alternative to the Burkert dark matter halo. This result should increase the empirical basis that justifies the usage of dark matter exponential models to adjust the observed rotation curves of real galaxies.