On the surface density of dark matter haloes

Abstract

In this article, we test the conclusion of Donato et al. (2009) concerning the universality of the DM halo surface density $\mu_{0D}=\rho_0r_0$. According to our study, the dispersion of values of $\mu_{0D}$ is twice higher than that found by Donato et al. (2009). We conclude, in contrast with Donato et al. (2009), that the DM surface density and its Newtonian acceleration are not constant but correlate with the luminosity, morphological type, $(B-V)_0$ colour index, and the content of neutral hydrogen. These DM parameters are higher for more luminous systems of early types with red colour and low gas content. We also found that the correlation of DM parameters with colour index appears to be the manifestation of a stronger relation between DM halo mass and the colour of a galaxy. This finding is in agreement with cosmological simulations (Guo et al, 2011). These results leave little room for the recently claimed universality of DM column density. We also found that isolated galaxies in our sample (contained in the Analysis of the interstellar Medium of Isolated GAlaxies (AMIGA) catalogue) do not differ significantly in their value of $\mu_{0D}$ from the entire sample. Thus, since the AMIGA catalogue gives a sample of galaxies that have not interacted with a significant mass neighbour in the past 3 Gyr, the difference between the systems with low and high values of $\mu_{0D}$ is not related to the merging events during this period of time.