2009/06/01 by Arunima Banerjee, Lynn D. Matthews, Chanda J. Jog · 1 citation
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1016/j.newast.2009.05.015
published as New Astron.15:89-95,2010 · 18 pages, 3 figures, Accepted for publication in New Astronomy
arxiv created 2009/06/01 · arxiv updated 2009/12/01
We model the shape and density profile of the dark matter halo of the low surface brightness, superthin galaxy UGC 7321, using the observed rotation curve and the HI scale height data as simultaneous constraints. We treat the galaxy as a gravitationally coupled system of stars and gas, responding to the gravitational potential of the dark matter halo. An isothermal halo of spherical shape with a core density in the range of 0.039 - 0.057 Msun/pc3 and a core radius between 2.5 - 2.9 kpc, gives the best fit to the observations for a range of realistic gas parameters assumed. We find that the best-fit core radius is only slightly higher than the stellar disc scale length (2.1 kpc), unlike the case of the high surface brightness galaxies where the halo core radius is typically 3-4 times the disc scale length of the stars. Thus our model shows that the dark matter halo dominates the dynamics of the low surface brightness, superthin galaxy UGC 7321 at all radii, including the inner parts of the galaxy.