Dark matter dominance at all radii in the superthin galaxy UGC 7321

Banerjee, Arunima and Matthews, Lynn D and Jog, Chanda J (2010) Dark matter dominance at all radii in the superthin galaxy UGC 7321. In: New Astronomy, 15 (1). pp. 89-95.

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Abstract

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 H i 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 View the MathML source and a core radius between 2.5 and 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.

Item Type:	Journal Article
Publication:	New Astronomy
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Galaxies:ISM;Galaxies:kinematics and dynamics;Galaxies:spiral;Galaxies:structure;Galaxies:halos;alaxies:individual:UGC 7321.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	29 Oct 2009 06:14
Last Modified:	19 Sep 2010 05:51
URI:	http://eprints.iisc.ac.in/id/eprint/24810

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