a1 Department of Physics, Macquarie University, Sydney NSW 2109, Australia
a2 Anglo-Australian Observatory, PO Box 296, Epping NSW 2121, Australia
Our R-band data show that the optical light from Malin 1 corresponds well with the >2-arcmin extent of the galaxy's Hı content and continues well beyond previously published V-band optical light radial profiles. Analysis of our image yields improved understanding of the galaxy's properties. We measure ellipticity of 0.20 ± 0.03, implying inclination of 38 ± 3°, and we trace the radial profile to 77arcsec. A single dusty spiral arm is also weakly discernable, and is consistent with the rotation direction of the Hı and spiral structure of the inner disk. Possible scenarios for the origin of the spiral structure are discussed.
(Received September 22 2006)
(Accepted February 19 2007)