Publications of the Astronomical Society of Australia

Research Article

Malin 1: A Deeper Look

Lesa Moorea1 c1 and Quentin A. Parkera1a2

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)


  • galaxies: evolution;
  • galaxies: fundamental parameters;
  • galaxies: individual (Malin 1);
  • techniques: image processing


c1 Corresponding author. E-mail: