Speaker
Anna Saburova
(Sternberg Astronomical institute of Moscow State University)
Description
We examined the reliability of estimates of pseudoisothermal, Burkert and NFW dark halo parameters for best fit models. To do it we constructed the chi^2 maps for the grid of the dark halo parameters for a sample of 14 disc galaxies with high quality rotation curves from THINGS. We showed that in a half of considered galaxies the best fit mass-modelling results are questionable. The trustworthiness of the estimate of the dark halo parameters depends on the shape and the extension of rotation curve and on the availability of detailed data for the central parts of the rotation curves. In general, the modelling with NFW profile fails more often in comparison to other profiles. The NFW profile usually corresponds to the masses that are two times higher than that for two other forms of a halo and to systematically lower disc mass-to-light ratios. Our results also demonstrated unreliability of the assumption of the universality of the dark matter halo column density. We made tests showing how the parameters of the three halo types change in the cases of a lack of kinematic data in the central or peripheral areas and for different spatial resolutions. The central densities rho0 and the characteristic radial scales Rs of dark halos appear to be quite uncertain, and there is an obvious degeneration between them. In contrast, the estimates of dark halo mass within optical borders are much more reliable.
Primary author
Anna Saburova
(Sternberg Astronomical institute of Moscow State University)
