HI synthesis observations of the blue compact dwarf NGC 1705

Australia Telescope Compact Array HI-line observations of the nearby dwarf galaxy NGC 1705 are presented. The data are used to trace the gravitational potential of the galaxy out to several stellar disc scalelengths. A rotation curve is derived for the system and used to generate mass models. Dark matter dominates the gravitational potential at nearly all galactocentric radii. NFW and pseudo-isothermal sphere halo parametrizations allow for good reproductions of the observations. The models suggest NGC 1705 to have a dark matter halo that is much denser and more compact than previously thought. © 2012 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.