We use high-quality optical rotation curves of nine low-luminosity disc galaxies to obtain the velocity profiles of the surrounding dark matter haloes. We find that they increase linearly with radius at least out to the edge of the stellar disc, implying that, over the entire stellar region, the density of the dark halo is about constant. The properties of the mass structure of these haloes are similar to those found for a number of dwarf and low surface brightness galaxies, but provide a more substantial evidence of the discrepancy between the halo mass distribution predicted in the cold dark matter scenario and those actually detected around galaxies. We find that the density law proposed by Burkert reproduces the halo rotation curves, with halo central densities (rho (0) similar to 1-4 x 10(-24) g cm(-3)) and core radii (r(0) similar to 5-15 kpc) scaling as rho (0) proportional to r(0)(-2/3).
The dark matter distribution in disc galaxies / Borriello, A; Salucci, Paolo. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 323:2(2001), pp. 285-292. [10.1046/j.1365-8711.2001.04077.x]
The dark matter distribution in disc galaxies
Salucci, Paolo
2001-01-01
Abstract
We use high-quality optical rotation curves of nine low-luminosity disc galaxies to obtain the velocity profiles of the surrounding dark matter haloes. We find that they increase linearly with radius at least out to the edge of the stellar disc, implying that, over the entire stellar region, the density of the dark halo is about constant. The properties of the mass structure of these haloes are similar to those found for a number of dwarf and low surface brightness galaxies, but provide a more substantial evidence of the discrepancy between the halo mass distribution predicted in the cold dark matter scenario and those actually detected around galaxies. We find that the density law proposed by Burkert reproduces the halo rotation curves, with halo central densities (rho (0) similar to 1-4 x 10(-24) g cm(-3)) and core radii (r(0) similar to 5-15 kpc) scaling as rho (0) proportional to r(0)(-2/3).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.